diff --git a/requirements.txt b/requirements.txt
index c0cffb3..4524151 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,8 +2,8 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-pbr>=2.0.0 # Apache-2.0
-Babel>=2.3.4 # BSD
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
+Babel!=2.4.0,>=2.3.4 # BSD
 cliff>=2.3.0 # Apache-2.0
 osc-lib>=1.2.0 # Apache-2.0
 oslo.utils>=3.20.0 # Apache-2.0