diff --git a/examples/flask_gevent/requirements.txt b/examples/flask_gevent/requirements.txt
index 4c024ca..328d779 100644
--- a/examples/flask_gevent/requirements.txt
+++ b/examples/flask_gevent/requirements.txt
@@ -1,6 +1,6 @@
 graphql_ws
 gevent
-flask
+flask==1.1.4
 flask_graphql
 flask_sockets
 graphene>=2.0