diff --git a/bower.json b/bower.json
index 7c5347f..b667fd1 100644
--- a/bower.json
+++ b/bower.json
@@ -2,7 +2,7 @@
   "name": "core-ajax",
   "private": true,
   "dependencies": {
-    "polymer": "Polymer/polymer#master"
+    "polymer": "Polymer/polymer#^0.4.0"
   },
   "devDependencies": {
     "polymer-test-tools": "Polymer/polymer-test-tools#master"