diff --git a/README.md b/README.md
index d38c618..2779f73 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,8 @@ const httpServer = createServer();
 
 const io = new Server(httpServer, {
   cors: {
-    origin: ["https://admin.socket.io"]
+    origin: ["https://admin.socket.io"],
+    credentials: true // needed for cookie-based sticky sessions, else you can ignore this line
   }
 });