I'd honestly just say "supports these OS's and these Phones" and tell everyone else to bugger off if they wanted to complain from a different handset or donate

I'd honestly just say "supports these OS's and these Phones" and tell everyone else to bugger off if they wanted to complain from a different handset or donate to the cause to get support for their platform. Discontinuing development and making a dramatic blog post about it doesn't really benefit anyone, including him.