That’s because it is rolling out availability to any Android user in the US who wants to use it, starting today.
iPhones do not support RCS, and over the past year, Apple has declined to comment on whether it ever will multiple times.
It gets even more complicated because the big four US carriers just announced that they will offer RCS in 2020.
In theory, you shouldn’t need to know exactly how it works because when carriers begin to offer their version of RCS chat, Android users will seamlessly switch over to their service.
In practice, however, it could get messy.
The worst-case scenario of carrier-made texting apps conflicting with Google’s own Android Messages app is still very much a possibility: