diff --git a/tox.ini b/tox.ini
index 37c1964a1e..c2e72de727 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 2.0
+minversion = 2.5.0
 skipsdist = True
 envlist = py36,py27,pep8,pypy