diff --git a/tox.ini b/tox.ini
index 629cb5a4..5b792cf3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,10 @@
 [tox]
 envlist = py26,py27,flake8
-minversion = 1.4.0
+minversion = 1.6
 
 [testenv]
 sitepackages = False
+install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          LANG=en_US.UTF-8
          LANGUAGE=en_US:en