diff --git a/test-requirements.txt b/test-requirements.txt
index acb1c98..15e29a7 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,4 +1,4 @@
-hacking
+hacking>=1.1,<1.2
 
 coverage>=3.6
 fixtures>=0.3.12
diff --git a/tox.ini b/tox.ini
index 4506c5f..4ef40f6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,4 +1,5 @@
 [tox]
+min_version = 3.1
 envlist = py35,py27,pypy,pep8
 skipdist = True
 ignore_basepython_conflict=true