Google and carriers deployed changes to RCS which have been breaking it for many users on the stock OS including with certain carriers and in whole countries. The changes appear to have specifically impacted GrapheneOS users too. It's not related to our September 8th update. We're working on it.
You can find many recent threads about people having issues with RCS in Google Messages while using a stock OS with Google Mobile Services. There are articles about how some carriers and countries no longer have it. It still works for most people but the changes definitely regressed compatibility.
GrapheneOS users were impacted by these recent changes much more than other users. We don't know why yet but we're working on determining that and restoring compatibility with Google Messages for people who use it. We'll try to get compatibility with the new way it functions implemented very soon.

@GrapheneOS

10 bucks on one of the components you stripped of permissions was used to dynamically pull in code that made it continue to work on the non-affected stock os devices.

@agowa338 The changes also broke it for many users on stock Google Mobile Services operating systems.

@GrapheneOS

"many != all". If there wasn't something different than it would either affect all of them or none...

Let us know when you discovered what fuckery they did this time and we'll know for sure.

I'd just expect it being something dynamically pulled from external that causes the the ones that still work to not have failed too at this point...

@agowa338 @GrapheneOS it broke for samsungs as well, my partner's phone normally does RCS by default, and he was asking me what the "RCS failed, delivered over SMS" messages he kept getting are. i just turned RCS off on his phone. I dont think samsung strips permissions for its messaging app, but it definitely adds and expands upon default google messages

@RetroRelics @GrapheneOS

GrapheneOS said it is something done in tandem with the carriers. So it could also be that it's the combination of device and carrier or something.

But so far that was just a dystopian guess from my side. Let's see what they discover and what actually caused this.

@agowa338 It's not broken for all GrapheneOS users, but it does seem broken for most.

@GrapheneOS

Even more interesting. Now I really want to know what is going on here.

@GrapheneOS isn't RCS a standard? how is it possible to break compatibility if they're implementing a standardised protocol?
@xyhhx Not in the same sense as SMS. It has anti-spam checks and they could make it require the Play Integrity API if they wanted.
@xyhhx @GrapheneOS unfortunately the decentralized, semi federated intended nature of it was undone when the carriers all gave up on serving it and switched to Google Jibe. So Google holds most of the cards and we are right back where we started with centralized messaging.
@GrapheneOS are there any official 'minimal' way of getting rcs? I gave up on it a couple of months ago, cause no guides worked.
@Re4mstr Google Messages is the only available option and is being quite hostile to being used elsewhere without privileged integration into the OS. We're going to work on fixing it but we can't guarantee it will work long term. We need an open source RCS app and it's not really clear how open RCS is to having alternate implementations. It's hard to see that as simply being openly allowed when Google Messages is mainly failing due to privileged verification checks it wants to do.

@GrapheneOS Also to my understanding there is no reason for this from a security perspective. To me if things such as Signal, Matrix apps, Therma, and Session can work then there is no reason this couldn't and still be "secure".

I don't like the security of RCS but it's better then nothing to me and also just convenient because it's hard to get people to use alternatives.

@emberfox The reason for it would be that it could have interoperable end-to-end encryption with Google Messages. iOS hasn't added RCS end-to-end encryption yet but supposedly will in the future. There will eventually be cross-platform end-to-end RCS encryption. For now, it's a proprietary Google Messages E2EE system and the current protocol is NOT being implemented by iOS but rather both Apple and Google are going to be implementing a new protocol.