diff --git a/tox.ini b/tox.ini
index 6a1b29f..948c3cd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
-minversion = 1.6
+minversion = 3.1.0
 skipsdist = True
-envlist = py27,py34
+envlist = venv
 
 [testenv:venv]
 basepython = python3