Enforce specific sockjs and sockjs-client version.

Ref #474

lib/Server.js

@@ -10,6 +10,7 @@ var https = require("https");
 var httpProxyMiddleware = require("http-proxy-middleware");
 var serveIndex = require("serve-index");
 var historyApiFallback = require("connect-history-api-fallback");
+var pkg = require("../package.json");
 
 function Server(compiler, options) {
 	// Default options
@@ -307,6 +308,9 @@ Server.prototype.setContentHeaders = function(req, res, next) {
 Server.prototype.listen = function() {
 	var returnValue = this.listeningApp.listen.apply(this.listeningApp, arguments);
 	var sockServer = sockjs.createServer({
+		// The SockJS server package uses a version of the client script
+		// that doesn't match our version of the client script.
+		sockjs_url: 'https://cdn.jsdelivr.net/sockjs/' + pkg.dependencies['sockjs-client'] + '/sockjs.min.js',
 		// Limit useless logs
 		log: function(severity, line) {
 			if(severity === "error") {

package.json

@@ -13,8 +13,8 @@
     "http-proxy-middleware": "~0.17.1",
     "opn": "4.0.2",
     "serve-index": "^1.7.2",
-    "sockjs": "^0.3.15",
-    "sockjs-client": "^1.0.3",
+    "sockjs": "0.3.17",
+    "sockjs-client": "1.1.1",
     "stream-cache": "~0.0.1",
     "strip-ansi": "^3.0.0",
     "supports-color": "^3.1.1",