diff --git a/extension/package.json b/extension/package.json
index eccc7a9..6ddc351 100644
--- a/extension/package.json
+++ b/extension/package.json
@@ -13,7 +13,7 @@
     "domready": "~1.0.7",
     "insert-css": "^0.2.0",
     "lodash": "^3.0.0",
-    "mercury": "^14.0.0",
+    "mercury": "^12.0.0",
     "xtend": "^4.0.0",
     "eventemitter2": "~0.4.14",
     "es6-shim": "^0.20.2",