Fluux XMPP is a Chat SDK in Swift for iOS, MacOS and Linux. It implements the XMPP protocol, which is an IETF standard. As a result, on iOS, we target iOS version 12+. On MacOS, we focus on Mojave and up (10.14+). On Linux, we use BSD Socket with SwiftNIO, so it should work quite broadly, as long as you have Swift 5.0+ installed.