diff --git a/requirements.txt b/requirements.txt
index 14038d8c..a43c6d4a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,6 +5,9 @@ setuptools
 # The setuptools package is required to install source distributions and on some systems is not installed by default.
 # Please keep it as the first item of this list.
 #
+click>=5.0
 pyserial>=3.0
 future>=0.15.2
 cryptography>=2.1.4
+pyparsing>=2.0.3,<2.4.0
+pyelftools>=0.22