diff --git a/package.json b/package.json
index addf2dd..aa3861f 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,7 @@
     "async": "^1.4.2",
     "autoprefixer-core": "^5.2.0",
     "babelify": "^6.3.0",
-    "clean-css": "^3.3.1",
+    "clean-css": "^4.2.1",
     "colors": "^1.1.2",
     "debug": "^2.2.0",
     "glob": "^5.0.15",