diff --git a/flask/requirements.txt b/flask/requirements.txt
index 0b564c0..55611cb 100644
--- a/flask/requirements.txt
+++ b/flask/requirements.txt
@@ -11,6 +11,6 @@ flask==1.1.2
 itsdangerous==1.1.0; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'
 jinja2==2.11.3; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'
 markupsafe==1.1.1; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3'
-waitress==2.0.0
+waitress==2.1.1
 werkzeug==1.0.1; python_version >= '2.7' and python_version not in '3.0, 3.1, 3.2, 3.3, 3.4'
 wheel==0.36.2