diff --git a/requirements.txt b/requirements.txt
index 4e8c93f242..9c2691627d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ pycrypto>=2.6
 eventlet>=0.13.0
 greenlet>=0.3.2
 httplib2
-iso8601>=0.1.4,!=0.1.5,!=0.1.6,!=0.1.7
+iso8601>=0.1.8
 kombu>=2.4.8
 argparse
 lxml>=2.3