For now, if you want to support Multiplay, you can email me
I'll add (later) the ability to donate, a forum for developers to help support multiplay, etc.
We want to expand to all platforms, Linux, Windows, Android, iOS. Even perhaps gaming platforms!! Why not?
Multiplay is built using C and SDL2. So it should be easy to port, assuming you are used to compiling for that platform. We have one small Mac-specific file, like 90 lines of code (mostly commented out), the rest compiles anywhere.
If you are a Windows/Android/Linux/Mac/iOS developer and want to help, let me know!