diff --git a/test-requirements.txt b/test-requirements.txt
index a44d121d33..83b6b0220d 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -8,7 +8,7 @@ fixtures<2.0,>=1.3.1 # Apache-2.0/BSD
 mock>=1.2 # BSD
 Babel!=2.3.0,!=2.3.1,!=2.3.2,!=2.3.3,>=1.3 # BSD
 PyMySQL>=0.6.2 # MIT License
-iso8601>=0.1.9 # MIT
+iso8601>=0.1.11 # MIT
 oslotest>=1.10.0 # Apache-2.0
 psycopg2>=2.5 # LGPL/ZPL
 python-ironicclient>=1.1.0 # Apache-2.0