update docs, remove other prints

Source/SocketIO/Engine/SocketEngine.swift

@@ -566,7 +566,6 @@ open class SocketEngine:
 
     private func sendPing() {
         guard connected, let pingInterval = pingInterval else {
-            print("not connected \(self.connected) or no ping interval \(self.pingInterval ?? -222)")
             return
         }
 
@@ -582,7 +581,6 @@ open class SocketEngine:
         engineQueue.asyncAfter(deadline: .now() + .milliseconds(pingInterval)) {[weak self, id = self.sid] in
             // Make sure not to ping old connections
             guard let this = self, this.sid == id else {
-                print("wrong ping?")
                 return
             }
 

Usage Docs/15to16.md

@@ -1,3 +1,16 @@
 # 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 sever
+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)])
+```
+
+