alt Hacker NewsRCS can be hit or miss on GrapheneOS, but they have made significant progress recently. It requires using Google Messages rather than any other messaging app, and may require enabling an ICC authentication option that is disabled by default. And it may depend on your carrier. RCS is kind of a pain in the butt but the messaging improvements over SMS are substantial which is why I wanted it.
When I first tried last fall I had it working for a few weeks then it stopped entirely delivering messages and I fell back to SMS only. After the recent system updates and enabling the ICC option it has been working well for me.
The official page explains briefly, https://grapheneos.org/usage#rcs
There is a very long discussion threat going back several years that is now considered resolved, which seems to be the case for me. https://discuss.grapheneos.org/d/1353-using-rcs-with-google-...
Replies
I've found that RCS works ok-ish on the Owner user, but doesn't work at all on any other (it appears as an empty message). Moving to the Owner account you can tap to redownload the message and then it appears correctly in all accounts. It's a mess that makes daily driving a secondary account not worth it
RCS barely works on regular Android.
In the last week or so, multiple people have told me they cannot text me. I found that I was getting a "verification limit exceeded" error (perhaps because of my unusual behavior of usually being at work or at home, both which have known wifi networks, and sending maybe half a dozen texts any day?). I got the error to go away for half a day and they were still unable to message during that time, and now that I have it disabled I still appear as online on RCS (yet still unreachable?) so they still cannot message me lol.
I've been on the other end many times across multiple Android devices across multiple years, being able to send messages to some RCS users, being unable to send messages to other RCS users, not being able to receive messages in group chats entirely comprised of Android users, etc.
SMS/MMS: Handled by carriers, you can send messages to people who are offline and they'll get the messages when they turn their phone back on.
Telegram/FbMessenger/Whatsapp/etc: Handled by individual corporations, you can send messages to people who are offline and they'll get the messages when they turn their their device on.
RCS: Handled by both Google and carriers at the same time for some reason, maybe 80% chance of being able to send a message to somebody who's online, let alone offline.
I'm sure there are multiple reasons it was challenging, but Google and friends have not risen to the occasion at all. Truly a garbage protocol.