diff --git a/tox.ini b/tox.ini
index e1eb31f..c9c91ad 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.1.0
+minversion = 3.18.0
 envlist = pep8
 skipsdist = True
 # this allows tox to infer the base python from the environment name