Compatible with Socket.io version 3
Serverless authentication (JWT)
Push messages to Slack
Limit connection times by client's IP address or UserID (unqiueToken)
Clients can publish to specific rooms.
Join multiple rooms
Firebase cloud messaging notifications (push notifications to mobile phones).
Client & server can be on separate servers.
Peer 2 Peer chat via webRTC (beta)
Docker
Scaling to multiple servers for the same app.