diff --git a/CMakeLists.txt b/CMakeLists.txt
index a57e36fdd..9e27ba41e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,7 +27,7 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(libcxx CXX C)
 
   set(PACKAGE_NAME libcxx)
-  set(PACKAGE_VERSION 8.0.0svn)
+  set(PACKAGE_VERSION 9.0.0svn)
   set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
   set(PACKAGE_BUGREPORT "llvm-bugs@lists.llvm.org")
 
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 20be9f627..29cee4418 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -1,5 +1,5 @@
 ========================================
-Libc++ 8.0.0 (In-Progress) Release Notes
+Libc++ 9.0.0 (In-Progress) Release Notes
 ========================================
 
 .. contents::
@@ -10,7 +10,7 @@ Written by the `Libc++ Team <https://libcxx.llvm.org>`_
 
 .. warning::
 
-   These are in-progress notes for the upcoming libc++ 8 release.
+   These are in-progress notes for the upcoming libc++ 9 release.
    Release notes for previous releases can be found on
    `the Download Page <https://releases.llvm.org/download.html>`_.
 
@@ -18,7 +18,7 @@ Introduction
 ============
 
 This document contains the release notes for the libc++ C++ Standard Library,
-part of the LLVM Compiler Infrastructure, release 8.0.0. Here we describe the
+part of the LLVM Compiler Infrastructure, release 9.0.0. Here we describe the
 status of libc++ in some detail, including major improvements from the previous
 release and new feature work. For the general LLVM release notes, see `the LLVM
 documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM releases may
@@ -32,7 +32,7 @@ main Libc++ web page, this document applies to the *next* release, not
 the current one. To see the release notes for a specific release, please
 see the `releases page <https://llvm.org/releases/>`_.
 
-What's New in Libc++ 8.0.0?
+What's New in Libc++ 9.0.0?
 ===========================
 
 New Features
@@ -40,23 +40,4 @@ New Features
 
 API Changes
 -----------
-- Building libc++ for Mac OSX 10.6 is not supported anymore.
-- Starting with LLVM 8.0.0, users that wish to link together translation units
-  built with different versions of libc++'s headers into the same final linked
-  image MUST define the _LIBCPP_HIDE_FROM_ABI_PER_TU macro to 1 when building
-  those translation units. Not defining _LIBCPP_HIDE_FROM_ABI_PER_TU to 1 and
-  linking translation units built with different versions of libc++'s headers
-  together may lead to ODR violations and ABI issues. On the flipside, code
-  size improvements should be expected for everyone not defining the macro.
-- Starting with LLVM 8.0.0, std::dynarray has been removed from the library.
-  std::dynarray was a feature proposed for C++14 that was pulled from the
-  Standard at the last minute and was never standardized. Since there are no
-  plans to standardize this facility it is being removed.
-- Starting with LLVM 8.0.0, std::bad_array_length has been removed from the
-  library. std::bad_array_length was a feature proposed for C++14 alongside
-  std::dynarray, but it never actually made it into the C++ Standard. There
-  are no plans to standardize this feature at this time. Formally speaking,
-  this removal constitutes an ABI break because the symbols were shipped in
-  the shared library. However, on macOS systems, the feature was not usable
-  because it was hidden behind availability annotations. We do not expect
-  any actual breakage to happen from this change.
+- ...
diff --git a/docs/conf.py b/docs/conf.py
index 50b372cf8..e88b2d337 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -47,9 +47,9 @@ copyright = u'2011-2018, LLVM Project'
 # built documents.
 #
 # The short X.Y version.
-version = '8.0'
+version = '9.0'
 # The full version, including alpha/beta/rc tags.
-release = '8.0'
+release = '9.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/include/__config b/include/__config
index f0bc3483f..f22819b71 100644
--- a/include/__config
+++ b/include/__config
@@ -33,7 +33,7 @@
 #  define _GNUC_VER_NEW 0
 #endif
 
-#define _LIBCPP_VERSION 8000
+#define _LIBCPP_VERSION 9000
 
 #ifndef _LIBCPP_ABI_VERSION
 #  define _LIBCPP_ABI_VERSION 1
diff --git a/include/__libcpp_version b/include/__libcpp_version
index e002b3628..d58c55a31 100644
--- a/include/__libcpp_version
+++ b/include/__libcpp_version
@@ -1 +1 @@
-8000
+9000