diff --git a/requirements.txt b/requirements.txt
index dd65da77..01de29c9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ pbr>=1.6 # Apache-2.0
 stevedore>=1.9.0 # Apache-2.0
 six>=1.9.0 # MIT
 enum34;python_version=='2.7' or python_version=='2.6' or python_version=='3.3' # BSD
-iso8601>=0.1.9 # MIT
+iso8601>=0.1.11 # MIT
 zake>=0.1.6 # Apache-2.0
 voluptuous>=0.8.6 # BSD License
 msgpack-python>=0.4.0 # Apache-2.0