diff --git a/requirements.txt b/requirements.txt
index 682867850..baf0855e8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ jsonschema==2.5.1
 gunicorn==19.6.0
 docopt==0.6.2
 six==1.10.0
-iso8601==0.1.11
+iso8601==0.1.12
 
 # pin to minor version 3.1.x
 notifications-python-client>=3.1,<3.2