diff --git a/optional-kubernetes-engine/requirements.txt b/optional-kubernetes-engine/requirements.txt
index 33ba8279..31e86fcb 100644
--- a/optional-kubernetes-engine/requirements.txt
+++ b/optional-kubernetes-engine/requirements.txt
@@ -3,7 +3,7 @@ google-cloud-datastore==1.7.1
 google-cloud-storage==1.23.0
 google-cloud-logging==1.8.0
 google-cloud-error_reporting==0.30.0
-gunicorn==19.9.0
+gunicorn==22.0.0
 oauth2client==4.1.3
 mock==2.0.0
 Flask-SQLAlchemy==2.3.2