Look here:
TeslaFi.com Firmware Tracker
And here:
Tesla Software Updates & Release Notes - Latest Tesla Updates
It's the same information presented differently.
Basic rules:
1) You cannot downgrade versions (notwithstanding anything Tesla might be able to do).
2) In order to get FSDb, you need a version that includes the FSDb stack.
3) If you currently do not have FSDb, and subsequently subscribe to FSD and request FSDb, your car will download a newer software version that has FSDb, if one is available.
4) Non-FSDb releases obviously do not have FSDb functionality.
It's more important to know what your car is currently on. For example, if your car is on 2023.12.9.1 or earlier, then it can download 2023.12.10 with 11.3.6 FSDb.
The fact that your car wants to update to 2023.12.5, then once you subscribe to FSD, and request FSDb, it should have no issues downloading 2023.12.10. How long that will take to pop up on your car, I do not know. I can only share what I observed back in May.
If your car is currently on 2023.6.100.1 or earlier, I wonder if it will download 2023.7.10 with FSDb 11.4.2. Note that even though this is an older infotainment version, the FSDb version is newer than 2023.12.10. Some people prefer the newer infotainment with the .12 release because there are many new features.