i will start a new installation (from scratch, only using (copy) some old rules etc.).
I have a Raspi 4; I see, for OpenHabian there is a Milestone 3.2 (32 Bit) and a Beta with 64 Bit.
Should I start directly with the 64 Bit OH?
Or can i update later from the 32 Bit to a stable 64 Bit?
Or make it no sense with a Raspi 4 to use the 64 Bit version?
See here for restrictions documented by the OS provider.
Basically, going down the 64bit path you may encounter incompatibilities or restrictions that do not apply to the 32bit version. If you want to avoid challenges like that, you may want to stay with the 32bit version. At a later time you can move to a 64bit version by backing up your OH stuff, reinstall the OS and restore your OH data and configuration from the (OH-)backup.
I would go as far as saying that it does not make sense to use the 64bit version. There’s no advantage to it, and if you have issues getting set up then you won’t know if the 64bit OS is contributing to the problem.
Personally, I think it’s best to start out with a stable build (currently 3.1), unless there’s a specific feature that you need in the milestone. If stable gives you issues that others have reported, you can see if they’ve been fixed in a milestone. Others think it’s better to just start with the milestone, though. Whatever makes you more comfortable.
Read the docs please before posting.