diff --git a/requirements.txt b/requirements.txt
index 13abfead2..f2bd9f6da 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ Babel>=1.3
 netaddr>=0.7.6
 falcon>=0.1.6,<0.2.0
 jsonschema>=2.0.0,<3.0.0
-iso8601>=0.1.8
+iso8601>=0.1.9
 msgpack-python
 MySQL-python
 posix_ipc