diff --git a/requirements.txt b/requirements.txt
index 40bf493b7..9ad25b113 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ pbr>=0.6,<1.0
 argparse
 cliff>=1.4.3
 httplib2>=0.7.5
-iso8601>=0.1.8
+iso8601>=0.1.9
 simplejson>=2.0.9
 six>=1.5.2
 Babel>=1.3