diff --git a/requirements.txt b/requirements.txt
index 769442c..921ab65 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 # 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.
-pbr>=2.0.0 # Apache-2.0
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
 cmd2>=0.6.7 # MIT
 PrettyTable<0.8,>=0.7.1 # BSD
 pyparsing>=2.1.0 # MIT