diff --git a/requirements.txt b/requirements.txt
index bc227e533..2fb9f4f87 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@
 # process, which may cause wedges in the gate later.
 pbr>=1.6 # Apache-2.0
 eventlet!=0.18.3,>=0.18.2 # MIT
-iso8601>=0.1.9 # MIT
+iso8601>=0.1.11 # MIT
 netaddr!=0.7.16,>=0.7.12 # BSD
 netifaces>=0.10.4 # MIT
 oslo.config>=3.9.0 # Apache-2.0