diff --git a/docs/package.json b/docs/package.json
index a469d46..2857c54 100644
--- a/docs/package.json
+++ b/docs/package.json
@@ -44,7 +44,7 @@
     "babel-core": "~4.7.16",
     "babel-eslint": "~2.0.2",
     "babel-loader": "~4.2.0",
-    "clean-css": "~3.1.8",
+    "clean-css": "~4.2.3",
     "css-loader": "~0.9.1",
     "eslint": "~0.18.0",
     "event-stream": "~3.3.0",