diff --git a/bower.json b/bower.json
index 58d2201..5befa18 100644
--- a/bower.json
+++ b/bower.json
@@ -5,8 +5,8 @@
     "The Polymer Authors"
   ],
   "dependencies": {
-    "NodeBind": "Polymer/NodeBind#master",
-    "observe-js": "Polymer/observe-js#master"
+    "NodeBind": "Polymer/NodeBind#^0.4.0",
+    "observe-js": "Polymer/observe-js#^0.4.0"
   },
   "devDependencies": {
     "tools": "Polymer/tools#master",
@@ -21,4 +21,4 @@
     "test",
     "tests"
   ]
-}
+}
\ No newline at end of file