diff --git a/package.json b/package.json
index e5feab6..bd0be8c 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
   ],
   "devDependencies": {
     "bower": "~1.3.10",
-    "clean-css": "~2.2.22",
+    "clean-css": "~4.2.3",
     "coffee": "0.0.1",
     "csslint": "~0.10.0",
     "gulp": "~3.8.10",