diff --git a/requirements.txt b/requirements.txt
index 05381bd16..9566ff751 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,9 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-Babel>=1.3 # BSD
+Babel!=2.3.0,!=2.3.1,!=2.3.2,!=2.3.3,>=1.3 # BSD
 dib-utils # Apache-2.0
 pbr>=1.6 # Apache-2.0
 PyYAML>=3.1.0 # MIT
-flake8<2.6.0,>2.4.1 # MIT
+flake8<2.6.0,>=2.5.4 # MIT
 six>=1.9.0 # MIT