diff --git a/tox.ini b/tox.ini
index 55edf001..0aa1d915 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.1
+minversion = 3.18.0
 envlist = pep8
 skipsdist = True
 ignore_basepython_conflict = True