diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index c2f4587f8..d8467a4e9 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1505,6 +1505,28 @@
  */
 //#define MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 
+/**
+ * \def MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+ *
+ * Enable TLS 1.3 middlebox compatibility mode.
+ *
+ * As specified in Section D.4 of RFC 8446, TLS 1.3 offers a compatibility
+ * mode to make a TLS 1.3 connection more likely to pass through middle boxes
+ * expecting TLS 1.2 traffic.
+ *
+ * Turning on the compatibility mode comes at the cost of a few added bytes
+ * on the wire, but it doesn't affect compatibility with TLS 1.3 implementations
+ * that don't use it. Therefore, unless transmission bandwidth is critical and
+ * you know that middlebox compatibility issues won't occur, it is therefore
+ * recommended to set this option.
+ *
+ * Comment to disable compatibility mode for TLS 1.3. If
+ * MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL is not enabled, this option does not
+ * have any effect on the build.
+ *
+ */
+//#define MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+
 /**
  * \def MBEDTLS_SSL_PROTO_DTLS
  *
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index c99e8f9a2..9dd9c4ab1 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -641,6 +641,9 @@ typedef enum
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
     MBEDTLS_SSL_ENCRYPTED_EXTENSIONS,
     MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY,
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED,
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
 }
 mbedtls_ssl_states;
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 296b62859..51e8ed7c6 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1676,6 +1676,11 @@ int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl );
  */
 int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl );
 
+/*
+ * Write of dummy-CCS's for middlebox compatibility
+ */
+int mbedtls_ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl );
+
 /*
  * Write TLS 1.3 handshake message tail
  */
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 286294f82..f7e40b123 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -3335,6 +3335,20 @@ static int ssl_prepare_record_content( mbedtls_ssl_context *ssl,
     MBEDTLS_SSL_DEBUG_BUF( 4, "input record from network",
                            rec->buf, rec->buf_len );
 
+    /*
+     * In TLS 1.3, always treat ChangeCipherSpec records
+     * as unencrypted. The only thing we do with them is
+     * check the length and content and ignore them.
+     */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
+    if( ssl->transform_in != NULL &&
+        ssl->transform_in->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 )
+    {
+        if( rec->type == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
+            done = 1;
+    }
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
+
     if( !done && ssl->transform_in != NULL )
     {
         unsigned char const old_msg_type = rec->type;
@@ -4385,6 +4399,21 @@ int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl )
             return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
         }
 #endif
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
+        if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_4 )
+        {
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+            MBEDTLS_SSL_DEBUG_MSG( 1,
+                ( "Ignore ChangeCipherSpec in TLS 1.3 compatibility mode" ) );
+            return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
+#else
+            MBEDTLS_SSL_DEBUG_MSG( 1,
+                ( "ChangeCipherSpec invalid in TLS 1.3 without compatibility mode" ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+        }
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
     }
 
     if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT )
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 1874d4fde..3327fce0e 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -723,8 +723,18 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
      * ( also known as ossification ). Otherwise, it MUST be set as a zero-length
      * vector ( i.e., a zero-valued single byte length field ).
      */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    MBEDTLS_SSL_CHK_BUF_PTR( p, end, ssl->session_negotiate->id_len + 1 );
+    *p++ = (unsigned char)ssl->session_negotiate->id_len;
+    memcpy( p, ssl->session_negotiate->id, ssl->session_negotiate->id_len );
+    p += ssl->session_negotiate->id_len;
+
+    MBEDTLS_SSL_DEBUG_BUF( 3, "session id", ssl->session_negotiate->id,
+                              ssl->session_negotiate->id_len );
+#else
     MBEDTLS_SSL_CHK_BUF_PTR( p, end, 1 );
     *p++ = 0; /* session id length set to zero */
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
 
     /* Write cipher_suites */
     ret = ssl_tls13_write_client_hello_cipher_suites( ssl, p, end, &output_len );
@@ -843,6 +853,24 @@ static int ssl_tls13_prepare_client_hello( mbedtls_ssl_context *ssl )
         return( ret );
     }
 
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    /*
+     * Create a session identifier for the purpose of middlebox compatibility
+     * only if one has not been created already.
+     */
+    if( ssl->session_negotiate->id_len == 0 )
+    {
+        /* Creating a session id with 32 byte length */
+        if( ( ret = ssl->conf->f_rng( ssl->conf->p_rng,
+                                      ssl->session_negotiate->id, 32 ) ) != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 1, "creating session id failed", ret );
+            return( ret );
+        }
+        ssl->session_negotiate->id_len = 32;
+    }
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
     return( 0 );
 }
 
@@ -1600,6 +1628,7 @@ static int ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl )
     return( 0 );
 }
 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
+
 /*
  * Handler for MBEDTLS_SSL_SERVER_FINISHED
  */
@@ -1611,11 +1640,35 @@ static int ssl_tls13_process_server_finished( mbedtls_ssl_context *ssl )
     if( ret != 0 )
         return( ret );
 
-    mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+    mbedtls_ssl_handshake_set_state(
+        ssl,
+        MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED );
+#else
     mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
+#endif
+
     return( 0 );
 }
 
+/*
+ * Handler for MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED
+ */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+static int ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl )
+{
+    int ret;
+
+    ret = mbedtls_ssl_tls13_write_change_cipher_spec( ssl );
+    if( ret != 0 )
+        return( ret );
+
+    mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
+
+    return( 0 );
+}
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
 /*
  * Handler for MBEDTLS_SSL_CLIENT_FINISHED
  */
@@ -1623,6 +1676,8 @@ static int ssl_tls13_write_client_finished( mbedtls_ssl_context *ssl )
 {
     int ret;
 
+    mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
+
     ret = mbedtls_ssl_tls13_write_finished_message( ssl );
     if( ret != 0 )
         return( ret );
@@ -1713,6 +1768,15 @@ int mbedtls_ssl_tls13_handshake_client_step( mbedtls_ssl_context *ssl )
             ret = ssl_tls13_handshake_wrapup( ssl );
             break;
 
+        /*
+         * Injection of dummy-CCS's for middlebox compatibility
+         */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+        case MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED:
+            ret = ssl_tls13_write_change_cipher_spec( ssl );
+            break;
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
         default:
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid state %d", ssl->state ) );
             return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 066147a5e..8b430de9d 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -1148,6 +1148,54 @@ void mbedtls_ssl_tls13_handshake_wrapup( mbedtls_ssl_context *ssl )
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= handshake wrapup" ) );
 }
 
+/*
+ *
+ * STATE HANDLING: Write ChangeCipherSpec
+ *
+ */
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+
+static int ssl_tls13_write_change_cipher_spec_body( mbedtls_ssl_context *ssl,
+                                                    unsigned char *buf,
+                                                    unsigned char *end,
+                                                    size_t *olen )
+{
+    ((void) ssl);
+
+    MBEDTLS_SSL_CHK_BUF_PTR( buf, end, 1 );
+    buf[0] = 1;
+    *olen = 1;
+
+    return( 0 );
+}
+
+int mbedtls_ssl_tls13_write_change_cipher_spec( mbedtls_ssl_context *ssl )
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write change cipher spec" ) );
+
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_flush_output( ssl ) );
+
+    /* Write CCS message */
+    MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_change_cipher_spec_body(
+                              ssl, ssl->out_msg,
+                              ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
+                              &ssl->out_msglen ) );
+
+    ssl->out_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC;
+
+    /* Dispatch message */
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_write_record( ssl, 1 ) );
+
+cleanup:
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write change cipher spec" ) );
+    return( ret );
+}
+
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
 
 #endif /* MBEDTLS_SSL_TLS_C */
diff --git a/tests/opt-testcases/tls13-compat.sh b/tests/opt-testcases/tls13-compat.sh
index 7b758088e..8cd0c3ef6 100755
--- a/tests/opt-testcases/tls13-compat.sh
+++ b/tests/opt-testcases/tls13-compat.sh
@@ -30,8 +30,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -47,8 +48,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -62,8 +64,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -79,8 +82,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -94,8 +98,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -111,8 +116,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -126,8 +132,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -143,8 +150,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -158,8 +166,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -175,8 +184,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -190,8 +200,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -207,8 +218,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -222,8 +234,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -239,8 +252,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -254,8 +268,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -271,8 +286,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -286,8 +302,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -303,8 +320,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -318,8 +336,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -335,8 +354,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -350,8 +370,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -367,8 +388,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -382,8 +404,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -399,8 +422,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -414,8 +438,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -431,8 +456,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -446,8 +472,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -463,8 +490,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -478,8 +506,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -495,8 +524,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -510,9 +540,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -528,9 +559,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -544,9 +576,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -562,9 +595,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -578,9 +612,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -596,9 +631,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -612,9 +648,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -630,9 +667,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -646,9 +684,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_GCM_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_GCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -664,9 +703,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_GCM_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-GCM:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-GCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -680,8 +720,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -697,8 +738,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -712,8 +754,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -729,8 +772,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -744,8 +788,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -761,8 +806,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -776,8 +822,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -793,8 +840,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -808,8 +856,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -825,8 +874,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -840,8 +890,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -857,8 +908,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -872,8 +924,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -889,8 +942,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -904,8 +958,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -921,8 +976,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -936,8 +992,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -953,8 +1010,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -968,8 +1026,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -985,8 +1044,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1000,8 +1060,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1017,8 +1078,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp256r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1032,8 +1094,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1049,8 +1112,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp384r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1064,8 +1128,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1081,8 +1146,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp521r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1096,8 +1162,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1113,8 +1180,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x25519,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1128,8 +1196,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1145,8 +1214,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x448,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1160,9 +1230,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp256r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1178,9 +1249,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp256r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP256R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1194,9 +1266,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp384r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1212,9 +1285,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp384r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP384R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1228,9 +1302,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,secp521r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1246,9 +1321,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,secp521r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-SECP521R1:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1262,9 +1338,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x25519,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1280,9 +1357,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x25519,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X25519:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1296,9 +1374,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_256_GCM_SHA384,x448,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_256_GCM_SHA384 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1314,9 +1393,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_256_GCM_SHA384,x448,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-256-GCM:+GROUP-X448:+SHA384:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-256-GCM-SHA384 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1330,8 +1410,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1347,8 +1428,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1362,8 +1444,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1379,8 +1462,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1394,8 +1478,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1411,8 +1496,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1426,8 +1512,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1443,8 +1530,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1458,8 +1546,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1475,8 +1564,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1490,8 +1580,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1507,8 +1598,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1522,8 +1614,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1539,8 +1632,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1554,8 +1648,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1571,8 +1666,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1586,8 +1682,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1603,8 +1700,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1618,8 +1716,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1635,8 +1734,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1650,8 +1750,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1667,8 +1768,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1682,8 +1784,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1699,8 +1802,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1714,8 +1818,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1731,8 +1836,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1746,8 +1852,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1763,8 +1870,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1778,8 +1886,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1795,8 +1904,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1810,9 +1920,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1828,9 +1939,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1844,9 +1956,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1862,9 +1975,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1878,9 +1992,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1896,9 +2011,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1912,9 +2028,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1930,9 +2047,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1946,9 +2064,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_CHACHA20_POLY1305_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_CHACHA20_POLY1305_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1964,9 +2083,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_CHACHA20_POLY1305_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+CHACHA20-POLY1305:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-CHACHA20-POLY1305-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -1980,8 +2100,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -1997,8 +2118,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2012,8 +2134,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2029,8 +2152,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2044,8 +2168,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2061,8 +2186,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2076,8 +2202,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2093,8 +2220,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2108,8 +2236,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2125,8 +2254,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2140,8 +2270,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2157,8 +2288,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2172,8 +2304,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2189,8 +2322,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2204,8 +2338,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2221,8 +2356,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2236,8 +2372,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2253,8 +2390,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2268,8 +2406,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2285,8 +2424,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2300,8 +2440,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2317,8 +2458,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2332,8 +2474,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2349,8 +2492,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2364,8 +2508,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2381,8 +2526,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2396,8 +2542,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2413,8 +2560,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2428,8 +2576,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2445,8 +2594,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2460,9 +2610,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2478,9 +2629,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2494,9 +2646,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2512,9 +2665,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2528,9 +2682,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2546,9 +2701,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2562,9 +2718,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2580,9 +2737,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2596,9 +2754,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2614,9 +2773,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2630,8 +2790,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2647,8 +2808,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2662,8 +2824,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2679,8 +2842,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp384r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2694,8 +2858,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2711,8 +2876,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=secp521r1,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2726,8 +2892,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2743,8 +2910,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x25519,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2758,8 +2926,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp256r1.crt -key data_files/ecdsa_secp256r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp256r1_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2775,8 +2944,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp256r1_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp256r1.crt --x509keyfile data_files/ecdsa_secp256r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp256r1_sha256 curves=x448,secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2790,8 +2960,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2807,8 +2978,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp256r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2822,8 +2994,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2839,8 +3012,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2854,8 +3028,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2871,8 +3046,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=secp521r1,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2886,8 +3062,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2903,8 +3080,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x25519,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2918,8 +3096,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp384r1.crt -key data_files/ecdsa_secp384r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp384r1_sha384 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2935,8 +3114,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp384r1_sha384" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp384r1.crt --x509keyfile data_files/ecdsa_secp384r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP384R1-SHA384:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp384r1_sha384 curves=x448,secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2950,8 +3130,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2967,8 +3148,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp256r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp256r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -2982,8 +3164,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -2999,8 +3182,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp384r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp384r1,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3014,8 +3198,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3031,8 +3216,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp521r1,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3046,8 +3232,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3063,8 +3250,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x25519,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x25519,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3078,8 +3266,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/ecdsa_secp521r1.crt -key data_files/ecdsa_secp521r1.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs ecdsa_secp521r1_sha512 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3095,8 +3284,9 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x448,ecdsa_secp521r1_sha512" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/ecdsa_secp521r1.crt --x509keyfile data_files/ecdsa_secp521r1.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-ECDSA-SECP521R1-SHA512:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca2.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=ecdsa_secp521r1_sha512 curves=x448,secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3110,9 +3300,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3128,9 +3319,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp256r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP256R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp256r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3144,9 +3336,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-384 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3162,9 +3355,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp384r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP384R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp384r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3178,9 +3372,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups P-521 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3196,9 +3391,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,secp521r1,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-SECP521R1:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=secp521r1" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3212,9 +3408,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X25519 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3230,9 +3427,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x25519,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X25519:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x25519" \
          0 \
          -c "HTTP/1.0 200 OK" \
@@ -3246,9 +3444,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->O: TLS_AES_128_CCM_8_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+         "$O_NEXT_SRV_NO_CERT -cert data_files/server2-sha256.crt -key data_files/server2.key -accept $SRV_PORT -ciphersuites TLS_AES_128_CCM_8_SHA256 -sigalgs rsa_pss_rsae_sha256 -groups X448 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 ok" \
@@ -3264,9 +3463,10 @@ requires_config_enabled MBEDTLS_DEBUG_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT
 run_test "TLS 1.3 m->G: TLS_AES_128_CCM_8_SHA256,x448,rsa_pss_rsae_sha256" \
-         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+         "$G_NEXT_SRV_NO_CERT --http --disable-client-cert --debug=4 --x509certfile data_files/server2-sha256.crt --x509keyfile data_files/server2.key --priority=NONE:+AEAD:+AES-128-CCM-8:+GROUP-X448:+SHA256:+SIGN-RSA-PSS-RSAE-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
          "$P_CLI server_addr=127.0.0.1 server_port=$SRV_PORT debug_level=4 force_version=tls13 ca_file=data_files/test-ca_cat12.crt force_ciphersuite=TLS1-3-AES-128-CCM-8-SHA256 sig_algs=rsa_pss_rsae_sha256 curves=x448" \
          0 \
          -c "HTTP/1.0 200 OK" \
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 9235be71e..eb67a7155 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -2725,8 +2725,22 @@ component_build_armcc () {
 
 component_test_tls13_experimental () {
     msg "build: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, without padding"
-    scripts/config.pl set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
-    scripts/config.pl set MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 1
+    scripts/config.py set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+    scripts/config.py set MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+    scripts/config.py set MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 1
+    CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+    make
+    msg "test: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, without padding"
+    make test
+    msg "ssl-opt.sh (TLS 1.3 experimental)"
+    if_build_succeeded tests/ssl-opt.sh
+}
+
+component_test_tls13_experimental_no_compatibility_mode () {
+    msg "build: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, without padding"
+    scripts/config.py set   MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+    scripts/config.py unset MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+    scripts/config.py set   MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 1
     CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
     make
     msg "test: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, without padding"
@@ -2737,8 +2751,9 @@ component_test_tls13_experimental () {
 
 component_test_tls13_experimental_with_padding () {
     msg "build: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, with padding"
-    scripts/config.pl set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
-    scripts/config.pl set MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 16
+    scripts/config.py set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+    scripts/config.py set MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+    scripts/config.py set MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 16
     CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
     make
     msg "test: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, with padding"
@@ -2750,6 +2765,7 @@ component_test_tls13_experimental_with_padding () {
 component_test_tls13_experimental_with_ecp_restartable () {
     msg "build: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, with ecp_restartable"
     scripts/config.py set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+    scripts/config.py set MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
     scripts/config.py set MBEDTLS_ECP_RESTARTABLE
     CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
     make
@@ -2762,6 +2778,7 @@ component_test_tls13_experimental_with_ecp_restartable () {
 component_test_tls13_experimental_with_everest () {
     msg "build: default config with MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL enabled, with Everest"
     scripts/config.py set MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+    scripts/config.py set MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
     scripts/config.py set MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED
     scripts/config.py unset MBEDTLS_ECP_RESTARTABLE
     CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
diff --git a/tests/scripts/generate_tls13_compat_tests.py b/tests/scripts/generate_tls13_compat_tests.py
index 07013aea4..4a4f8fa42 100755
--- a/tests/scripts/generate_tls13_compat_tests.py
+++ b/tests/scripts/generate_tls13_compat_tests.py
@@ -76,13 +76,14 @@ class TLSProgram(metaclass=abc.ABCMeta):
     Base class for generate server/client command.
     """
 
-    def __init__(self, ciphersuite, signature_algorithm, named_group):
+    def __init__(self, ciphersuite, signature_algorithm, named_group, compat_mode=True):
         self._ciphers = []
         self._sig_algs = []
         self._named_groups = []
         self.add_ciphersuites(ciphersuite)
         self.add_named_groups(named_group)
         self.add_signature_algorithms(signature_algorithm)
+        self._compat_mode = compat_mode
 
     # add_ciphersuites should not override by sub class
     def add_ciphersuites(self, *ciphersuites):
@@ -138,7 +139,10 @@ class OpenSSLServ(TLSProgram):
                 "-sigalgs {signature_algorithms}".format(
                     signature_algorithms=signature_algorithms),
                 "-groups {named_groups}".format(named_groups=named_groups)]
-        ret += ['-msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache']
+        ret += ['-msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache']
+        if not self._compat_mode:
+            ret += ['-no_middlebox']
+
         return ' '.join(ret)
 
     def pre_checks(self):
@@ -221,7 +225,10 @@ class GnuTLSServ(TLSProgram):
         priority_string_list = ['NONE'] + sorted(priority_string_list) + ['VERS-TLS1.3']
 
         priority_string = ':+'.join(priority_string_list)
-        priority_string += ':%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE'
+        priority_string += ':%NO_TICKETS'
+        if not self._compat_mode:
+            priority_string += [':%DISABLE_TLS13_COMPAT_MODE']
+
         ret += ['--priority={priority_string}'.format(
             priority_string=priority_string)]
         ret = ' '.join(ret)
@@ -273,6 +280,10 @@ class MbedTLSCli(TLSProgram):
                'requires_config_enabled MBEDTLS_SSL_CLI_C',
                'requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL',
                'requires_config_disabled MBEDTLS_USE_PSA_CRYPTO']
+
+        if self._compat_mode:
+            ret += ['requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE']
+
         if 'rsa_pss_rsae_sha256' in self._sig_algs:
             ret.append(
                 'requires_config_enabled MBEDTLS_X509_RSASSA_PSS_SUPPORT')
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index d5e9e0199..97c4ee395 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -8769,7 +8769,6 @@ run_test    "export keys functionality" \
 
 # openssl feature tests: check if tls1.3 exists.
 requires_openssl_tls1_3
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 run_test    "TLS 1.3: Test openssl tls1_3 feature" \
             "$O_NEXT_SRV -tls1_3 -msg" \
             "$O_NEXT_CLI -tls1_3 -msg" \
@@ -8781,7 +8780,6 @@ run_test    "TLS 1.3: Test openssl tls1_3 feature" \
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
 requires_gnutls_next_disable_tls13_compat
-requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
 run_test    "TLS 1.3: Test gnutls tls1_3 feature" \
             "$G_NEXT_SRV --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE --disable-client-cert " \
             "$G_NEXT_CLI localhost --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE -V" \
@@ -8814,9 +8812,12 @@ run_test    "TLS 1.3: handshake dispatch test: tls13 only" \
 
 requires_openssl_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 run_test    "TLS 1.3: minimal feature sets - openssl" \
-            "$O_NEXT_SRV -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+            "$O_NEXT_SRV -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
             "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
             0 \
             -c "tls13 client state: 0"     \
@@ -8843,11 +8844,13 @@ run_test    "TLS 1.3: minimal feature sets - openssl" \
 
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
-requires_gnutls_next_disable_tls13_compat
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 run_test    "TLS 1.3: minimal feature sets - gnutls" \
-            "$G_NEXT_SRV --debug=4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE --disable-client-cert" \
+            "$G_NEXT_SRV --debug=4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS --disable-client-cert" \
             "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
             0 \
             -s "SERVER HELLO was queued"   \
@@ -8874,6 +8877,8 @@ run_test    "TLS 1.3: minimal feature sets - gnutls" \
             -c "HTTP/1.0 200 OK"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_gnutls_tls1_3
 run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.0" \
@@ -8886,6 +8891,8 @@ run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.0" \
             -C "Protocol is TLSv1.0"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_gnutls_tls1_3
 run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.1" \
@@ -8898,6 +8905,8 @@ run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.1" \
             -C "Protocol is TLSv1.1"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_gnutls_tls1_3
 run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.2" \
@@ -8910,6 +8919,8 @@ run_test    "TLS 1.3:Not supported version check:gnutls: srv max TLS 1.2" \
             -C "Protocol is TLSv1.2"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_openssl_next
 run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.0" \
@@ -8922,6 +8933,8 @@ run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.0" \
             -C "Protocol  : TLSv1.0"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_openssl_next
 run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.1" \
@@ -8934,6 +8947,8 @@ run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.1" \
             -C "Protocol  : TLSv1.1"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 skip_handshake_stage_check
 requires_openssl_next
 run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.2" \
@@ -8947,29 +8962,37 @@ run_test    "TLS 1.3:Not supported version check:openssl: srv max TLS 1.2" \
 
 requires_openssl_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 run_test    "TLS 1.3: CertificateRequest check - openssl" \
-            "$O_NEXT_SRV -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache -Verify 10" \
+            "$O_NEXT_SRV -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache -Verify 10" \
             "$P_CLI debug_level=4 force_version=tls13 " \
             1 \
             -c "CertificateRequest not supported"
 
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
-requires_gnutls_next_disable_tls13_compat
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 run_test    "TLS 1.3: CertificateRequest check - gnutls" \
-            "$G_NEXT_SRV --debug=4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+            "$G_NEXT_SRV --debug=4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS" \
             "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
             1 \
             -c "CertificateRequest not supported"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 requires_openssl_tls1_3
 run_test    "TLS 1.3: HelloRetryRequest check - openssl" \
-            "$O_NEXT_SRV -ciphersuites TLS_AES_256_GCM_SHA384  -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+            "$O_NEXT_SRV -ciphersuites TLS_AES_256_GCM_SHA384  -sigalgs ecdsa_secp256r1_sha256 -groups P-256 -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
             "$P_CLI debug_level=4 force_version=tls13" \
             1 \
             -c "received HelloRetryRequest message" \
@@ -8978,22 +9001,76 @@ run_test    "TLS 1.3: HelloRetryRequest check - openssl" \
 
 requires_gnutls_tls1_3
 requires_gnutls_next_no_ticket
-requires_gnutls_next_disable_tls13_compat
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
 run_test    "TLS 1.3: HelloRetryRequest check - gnutls" \
-            "$G_NEXT_SRV -d 4 --priority=NONE:+GROUP-SECP256R1:+AES-256-GCM:+SHA384:+AEAD:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE" \
+            "$G_NEXT_SRV -d 4 --priority=NONE:+GROUP-SECP256R1:+AES-256-GCM:+SHA384:+AEAD:+SIGN-ECDSA-SECP256R1-SHA256:+VERS-TLS1.3:%NO_TICKETS" \
             "$P_CLI debug_level=4 force_version=tls13" \
             1 \
             -c "received HelloRetryRequest message" \
             -c "HRR not supported" \
             -c "Last error was: -0x6E00 - SSL - The handshake negotiation failed" \
             -s "HELLO RETRY REQUEST was queued"
+
 for i in $(ls opt-testcases/*.sh)
 do
     . $i
 done
 
+requires_openssl_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_disabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+run_test    "TLS 1.3 m->O both peers do not support middlebox compatibility" \
+            "$O_NEXT_SRV -msg -tls1_3 -no_middlebox -num_tickets 0 -no_resume_ephemeral -no_cache" \
+            "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
+            0 \
+            -c "HTTP/1.0 200 ok"
+
+requires_openssl_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_disabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+run_test    "TLS 1.3 m->O server with middlebox compat support, not client" \
+            "$O_NEXT_SRV -msg -tls1_3 -num_tickets 0 -no_resume_ephemeral -no_cache" \
+            "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
+            1 \
+            -c "ChangeCipherSpec invalid in TLS 1.3 without compatibility mode"
+
+requires_gnutls_tls1_3
+requires_gnutls_next_no_ticket
+requires_gnutls_next_disable_tls13_compat
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_disabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+run_test    "TLS 1.3 m->G both peers do not support middlebox compatibility" \
+            "$G_NEXT_SRV --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS:%DISABLE_TLS13_COMPAT_MODE --disable-client-cert" \
+            "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
+            0 \
+            -c "HTTP/1.0 200 OK"
+
+requires_gnutls_tls1_3
+requires_gnutls_next_no_ticket
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
+requires_config_disabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_CLI_C
+requires_config_disabled MBEDTLS_USE_PSA_CRYPTO
+run_test    "TLS 1.3 m->G server with middlebox compat support, not client" \
+            "$G_NEXT_SRV --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:+CIPHER-ALL:%NO_TICKETS --disable-client-cert" \
+            "$P_CLI debug_level=3 min_version=tls13 max_version=tls13" \
+            1 \
+            -c "ChangeCipherSpec invalid in TLS 1.3 without compatibility mode"
+
 # Test heap memory usage after handshake
 requires_config_enabled MBEDTLS_MEMORY_DEBUG
 requires_config_enabled MBEDTLS_MEMORY_BUFFER_ALLOC_C