# Upgrading from v15 to v16

This guide will help you navigate the changes that were introduced in v16.

## Objective-c is no longer supported. You must now use Swift.

## Client supports multiple socket.io versions

The client now supports socket.io 3 servers. This is mostly a transparent change, however if your server
is socket.io 2, you must send `.version(.two)` as an option to the manager.

```swift
SocketManager(socketURL: URL(string:"http://localhost:8087/")!, config: [.version(.two)])
```