Our next release successfully works around their ban on using GrapheneOS.
We've changed ro.build.host and ro.build.user (the build hostname and username) from grapheneos to other values. Nearly any other values work for those fields. Likely the only ones that are banned are ones consistently used by other aftermarket operating systems at least if they set them to a constant value as we do for reproducible builds. We chose to set them to android-user and r-0123456789abcdef-0123 to match the format currently used for the stock Pixel OS builds, which is specific to Google's build syste, and has changed multiple times over the years. Other devices do it differently. We don't expect any more issues from those.
Revolt also bans having ro.boot.verifiedbootstate set to yellow indicating using an aftermarket OS with the device locked and verified boot enabled. For some reason, they do permit ro.boot.verifiedbootstate being orange which means an unlocked device likely running a modified or aftermarket OS without security intact since at the very least verified boot and attestation are disabled, but likely much more security is lost too. They also don't use their checks on a userdebug build. To handle this, we're using standard infrastructure for setting compatibility values for properties for apps, which we've limited to user installed apps. In the future, we can also use this to match the stock OS build number, build hostname and other values if it ever proves necessary. We could do that proactively before we find apps banning GrapheneOS based on it in case some exist, but they probably don't so we probably won't do it without a known app requiring it.
It's incredibly strange that Revolut does this kind of nonsense. It's not clear what they're trying to achieve beyond harming GrapheneOS users. They haven't banned having a highly insecure device with no patches for 10 years and haven't even banned having the device unlocked with any aftermarket OS on it. They specifically banned having the device locked with an aftermarket OS or specifically having GrapheneOS. They also specifically banned several other aftermarket operating systems including LineageOS but those don't preserve the standard security model or set an honest security patch level so at least that could be weakly justified. Even that doesn't hold up to scrutiny when they permit a stock OS with no patches for 10 years and clearly unlocked devices. It's a complete joke.