We took the decision to rename the repository because any attempts to upgrade ended up in a pickle, so v3 is intentionally a dead end. Best to stick on v3 and wait for v5?, but for the crazy you could rename (s/buster/planet) the line in a few places in your apt sources/pinning files if you want to live off the edge of the map with the dragons.
I think the camera can only work in v4 though haven't tested it as the whole point of the move is to give the same level of HW support as with UBPorts. The breaking change is moving from droid-hal-cosmopda-bin built from a subset of the private sources and installed without lxc containment and so not upgradable neither to itself nor to lxc-android that is built from LineageOS and due to being inside a .img file is upgradable in the future if needed. We did try to put droid-hal back to one from a backup but turned out to be an older one than that in v3 so we just gave up and so we got the one time forced upgrade. As a sweeter for that forced re-install I did the installer work where you can pick the keyboard/timezone at installation.
I do apologise for not testing calls-in, I did test sms-in/out and calls-out, I just assumed if sms-in worked then as calls-out worked so would calls-in. I did offer pre-release testing to four other people though apparently none of them thought to try incoming calls either. I've generally considered the lack of sleep performance would preclude the use as a telephone also the fact that a pocket crash reboot* will drop you out of any chance of calls/sms working until you've logged in again. Its on the list to investigate along with the BT having only ever worked on first boot after fresh v4 install and never again.
Bugs:
https://github.com/gemian/gemian/issuesWork prioritisation:
https://gemian.thinkglobally.org/sponsor-hub/ (no actual need to be a sponsor despite the name - clearly need more testers)
Chip in:
https://github.com/gemian/gemian/wiki/FundingOptions* I think I was getting about one a month on Gemini when I actually left the house - zero when its sat on the desk all the time in these C19 times.