diff --git a/2013-05/requirements.txt b/2013-05/requirements.txt
index b3fe1f1..32c3655 100644
--- a/2013-05/requirements.txt
+++ b/2013-05/requirements.txt
@@ -7,7 +7,7 @@ zdaemon==3.0.5
 zope.event==4.0.1
 zope.interface==4.0.2
 Flask-Script==0.5.1
-Flask==0.9
+Flask==1.0
 Jinja2==2.6
 Werkzeug==0.8.3
 path.py==2.4.1