diff --git a/requirements-dev.txt b/requirements-dev.txt
index 127d991..9a00ee3 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,4 +1,4 @@
-tox==3.7.0
+tox==3.28.0
 pytest==4.3.0
 coverage==4.5.3
 mock==2.0.0