Overall release notes for 2023.12.1 are posted and there are other threads about the new features in the service menu for the newer cars (3/Y) but I wanted to show you what the few options are for the legacy model S/X (my specs in signature). We dont get all the cool stuff that the newer models have but we now have feature for coolant fill and purge, thermal test, door handle information, and a BMS reset button. The coolant tools were there in 2023.6 but the door handle and battery BMS reset seem to be new. I havent used any of these items but I like the idea that Tesla is slowly adding the ability for 3rd party people to do basic repair tasks on their vehicles.