diff --git a/requirements.txt b/requirements.txt
index 055bf42b5..2e691aeb0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 argparse
 Babel>=1.3
-iso8601>=0.1.8
+iso8601>=0.1.9
 netaddr>=0.7.6
 oslo.config>=1.2.0
 pbr>=0.6,<1.0