diff --git a/tox.ini b/tox.ini
index 2505b3e10..0c3c58f8d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,7 +17,7 @@ deps =
     beautifulsoup4==4.4.1
     coverage==4.1
     decorator==4.0.9
-    Flask==0.11.0
+    Flask==0.10.1
     glob2==0.4.1
     httpbin==0.4.1
     hypothesis==3.4.0