diff --git a/requirements.txt b/requirements.txt
index 93c4d809a..5e63740d1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,4 @@ Babel>=1.3
 argparse
 dib-utils # Apache-2.0
 PyYAML>=3.1.0
+flake8>=2.2.4,<=2.4.1