diff --git a/requirements.txt b/requirements.txt
index 8180d8f..a7d1656 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,5 +10,5 @@ oslo.config>=1.6.0  # Apache-2.0
 oslo.i18n>=1.3.0  # Apache-2.0
 oslo.utils>=1.2.0                       # Apache-2.0
 posix_ipc
-six>=1.7.0
+six>=1.9.0
 retrying>=1.2.3,!=1.3.0 # Apache-2.0