Are there any foss RCS apps or is it still exclusive to Google’s messages app? I feel like it would be 2 steps forward 1 step back for me to quit Google photos for immich and then exchange aosp messaging for Google messages.
Still exclusive to Google/Samsung proprietary apps. AFAIK they also do extensive SafetyNet attestation checks, so it isn’t even possible requires a bit of work (see below) to use RCS on a custom ROM like GrapheneOS, CalyxOS, DivestOS, or LineageOS, or even a rooted stock OS. Unless that does a complete 180°, I’m sticking with Signal
RCS worked for me with Google’s messages app and GrapheneOS. Took a bit for it to verify and start working but once it did I had no issues. I’ve since switched to QKSMS and now the only google app on my phone is play store services.
That is incorrect. It is possible to use RCS on GrapheneOS at least. You need to install Sandboxed Google Play Services, the Carrier Services app, and then go to Settings -> Apps -> Sandboxed Google Play -> Google Settings -> Mobile Data and Messaging -> Phone Number Verification -> Toggle on ‘Automatically Verify Phone Number’.
Also install Google Messages from the Play Store with a dummy account and then log out of that account / delete it.
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