diff --git a/09_NodeChatroom/package.json b/09_NodeChatroom/package.json
index c60a0e2..eb1a75d 100644
--- a/09_NodeChatroom/package.json
+++ b/09_NodeChatroom/package.json
@@ -11,7 +11,7 @@
     "express": "^4.0.0",
     "jade": "*",
     "mongodb": "^3.1.13",
-    "socket.io": "^1.0.6",
+    "socket.io": "^4.0.0",
     "stylus": "^0.49.1"
   }
 }