Google provides RCS (Rich Communication Services) messaging for Android devices. Google works with carriers and OEMs to offer the Messages for RCS app, which supports interoperability across devices and operator networks.
Yes, that's true. I was just wondering because a few family members of mine have AT&T, who also have samsung phones, and their phones support RCS samsung messages.
T-Mobile supports RCS messaging through its Advanced Messaging feature, but you need to use the Google Messages app to send and receive RCS messages.
Notice, you're on T-Mobile and they are on ATT. Certain features are carrier specific.
Google works with all these companies, but it's up to them if they choose to use it or not. And T-Mobile just chose to keep RCS for the Google Messages app only.
