diff --git a/requirements.txt b/requirements.txt
index bb2f117..8579f94 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,12 +2,12 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-Babel>=2.3.4 # BSD
+Babel!=2.4.0,>=2.3.4 # BSD
 cliff>=2.3.0 # Apache-2.0
 osc-lib>=1.2.0 # Apache-2.0
 oslo.i18n>=2.1.0 # Apache-2.0
 oslo.utils>=3.20.0 # Apache-2.0
-pbr>=2.0.0 # Apache-2.0
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
 PrettyTable<0.8,>=0.7.1 # BSD
 keystoneauth1>=2.18.0 # Apache-2.0
 six>=1.9.0 # MIT