diff --git a/tox.ini b/tox.ini
index 8e6b2bf..153ebbf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 2.0
+minversion = 3.1.1
 envlist = py3,pypy,pep8
 skipsdist = True