diff --git a/tools/pip-requires b/tools/pip-requires
index f517a02..be32c44 100644
--- a/tools/pip-requires
+++ b/tools/pip-requires
@@ -1,4 +1,4 @@
 argparse
 httplib2
-prettytable==0.6
+prettytable>=0.6,<0.7
 python-keystoneclient>=0.1,<0.2