diff --git a/index-dev.html b/index-dev.html
index 56d8a6a3..47ae99fb 100644
--- a/index-dev.html
+++ b/index-dev.html
@@ -33,8 +33,8 @@
     <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
     <script crossorigin src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
     <!-- Firebase push notifications. -->
-    <script crossorigin src="https://unpkg.com/firebase@5/firebase-app.js"></script>
-    <script crossorigin src="https://unpkg.com/firebase@5/firebase-messaging.js"></script>
+    <script crossorigin src="https://unpkg.com/firebase@5.5.0/firebase-app.js"></script>
+    <script crossorigin src="https://unpkg.com/firebase@5.5.0/firebase-messaging.js"></script>
   </head>
 
   <body>