diff --git a/package.json b/package.json
index d86df8e..af0ede8 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
     "underscore": "~1.5.1",
     "express": "~4.17.0",
     "mustache": "~3.0.0",
-    "socket.io": "~0.9.16"
+    "socket.io": "~4.0.0"
   },
   "devDependencies": {
     "grunt-contrib-qunit": "0.5.2",