diff --git a/requirements.txt b/requirements.txt
index 2bc1a9923..c37705a19 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,4 +8,4 @@ setuptools
 pyserial>=3.0
 future>=0.15.2
 cryptography>=2.1.4
-pyparsing>=2.0.3,<2.4.0
+pyparsing>=2.0.3,!=2.4.0