using sync framework on cross platform

Question

HI,

I am a .Net developer, and now i have to develop an application which synchronize file from client system to cloud server.

This application should be cross platform(Windows, Linux, Mac  OS).

Under FAQ of Microsoft sync framework, I have read that we can develop an application for non windows platform  through commercial licensing and porting kits. it will be helpful if you give information about this as soon as possible. 

Regards