diff --git a/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/echo.html b/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/echo.html
index 42081d4e19..0ffca05b4d 100644
--- a/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/echo.html
+++ b/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/echo.html
@@ -49,7 +49,7 @@
             margin: 0;
         }
     </style>
-    <script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/sockjs/0.3.4/sockjs.min.js"></script>
     <script type="text/javascript">
         var ws = null;
 
diff --git a/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/snake.html b/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/snake.html
index be3b6b388d..5728fc0144 100644
--- a/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/snake.html
+++ b/spring-boot-samples/spring-boot-sample-websocket/src/main/resources/static/snake.html
@@ -49,12 +49,12 @@
             margin: 0;
         }
     </style>
-    <script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/sockjs/0.3.4/sockjs.min.js"></script>
 </head>
 <body>
     <noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable
     Javascript and reload this page!</h2></noscript>
-    
+
     <div style="float: left">
         <canvas id="playground" width="640" height="480"></canvas>
     </div>
