diff --git a/requirements.txt b/requirements.txt
index ae6cc7c..06e2755 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,7 +9,7 @@
 
 pbr>=0.6,!=0.7,<1.0
 Babel>=1.3
-six>=1.7.0
+six>=1.9.0
 msgpack-python>=0.4.0
 # Only for timeutils in openstack.common - once we're using the
 # library version this can be removed.