diff --git a/package.json b/package.json
index e3f27dd..c0c7b05 100644
--- a/package.json
+++ b/package.json
@@ -17,7 +17,7 @@
     "devDependencies" :
         {"browserify" : "6.2.x",
          "uglify-js"  : "2.4.x",
-         "clean-css"  : "2.2.x",
+         "clean-css"  : "4.2.x",
          "through"    : "2.3.x"},
     "repository" :
         {"type" : "git",