diff --git a/web/flask/mega_tutorial/chapter16-elasticsearch/app/requirements.txt b/web/flask/mega_tutorial/chapter16-elasticsearch/app/requirements.txt
index 454923d..90d7c02 100644
--- a/web/flask/mega_tutorial/chapter16-elasticsearch/app/requirements.txt
+++ b/web/flask/mega_tutorial/chapter16-elasticsearch/app/requirements.txt
@@ -23,7 +23,7 @@ idna==2.8
 image==1.5.27
 itsdangerous==1.1.0
 Jinja2==2.10.1
-Mako==1.1.0
+Mako==1.2.2
 MarkupSafe==1.1.1
 Pillow==6.1.0
 PyJWT==1.7.1