diff --git a/tox.ini b/tox.ini
index 6dfecc57e5..8a7704c824 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,11 +1,13 @@
 [tox]
-minversion = 1.6
+minversion = 1.8
 skipsdist = True
 envlist = py34,py27,pep8
 
 [testenv]
 usedevelop = True
-install_command = pip install -U {opts} {packages}
+install_command =
+                  constraints: pip install -U --force-reinstall -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
+                  pip install -U {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          PYTHONDONTWRITEBYTECODE = 1
          LANGUAGE=en_US