diff --git a/requirements.txt b/requirements.txt
index db1aec4c99..1115fec2d2 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -23,7 +23,7 @@ python-keystoneclient!=1.8.0,!=2.1.0,>=1.6.0 # Apache-2.0
 python-swiftclient>=2.2.0 # Apache-2.0
 python-designateclient>=1.5.0 # Apache-2.0
 python-neutronclient>=4.2.0 # Apache-2.0
-iso8601>=0.1.9 # MIT
+iso8601>=0.1.11 # MIT
 jsonschema!=2.5.0,<3.0.0,>=2.0.0 # MIT
 Jinja2>=2.8 # BSD License (3 clause)
 pexpect!=3.3,>=3.1 # ISC License