My RCS number is +1 4126829751. My carrier finally supports RCS on iPhones, and a friend verified that to me. There is nothing much to say about that. RCS is the successor to SMS, and even uses the SMS link for starting the application to send an RCS message. With growing support for carriers, and iPhones, the only devices that do not support RCS will include basic phones including those running KaiOS, however – I feel that KaiOS should also support RCS, however I am not the developer, so I can’t make those changes.