diff --git a/requirements.txt b/requirements.txt
index 67d352c..97bf932 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@
 # be installed in a specific order.
 #
 # PBR should always appear first
-pbr>=2.0.0 # Apache-2.0
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
 # If python-zunclient will be released, we will use it.
 #python-zunclient>=0.0.1 # Apache-2.0
 Babel!=2.4.0,>=2.3.4 # BSD