I have a TCP app running that was written in Objective-C on iOS 10.3.3 on ipads. We have over a hundred, so upgrading them is not an option. I need to update the app to Swift. I am having an issue finding equivalent code for my communications. In O-C I have: socketQueue = dispatch_queue_create("socketQueue", NULL); listenSocket = ([GCDAsyncSocket alloc] initWIthDelegate:self delegateQueue:socketQueue]; [self startTCPListener] ////// startTCPListener /////// int port = xxxx; NSError * error - nil; if (![listenSocket acceptOnPort:port error:&error]) { // error } Can someone please give me an example that is Swift-compliant and also on iOS 10.3.3 (cannot use await/async)? Thank you, jerry