diff --git a/requirements-dev.txt b/requirements-dev.txt
index 3d2e136..8e9c88d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -10,4 +10,4 @@ pep8-naming==0.4.1
 pre-commit==0.9.1
 py==1.4.31
 pytest==3.0.3
-tox==2.3.1
+tox==2.4.0