Perhaps it can Move the files, but what about inside your rules, sitemaps, configs of bindings and much more. Don’t expect a 100% smooth upgrade. You are going to need to spend hours fixing spot fires when making such a big jump. I would setup a test server or second hard drive you swap out to get it going and then move over when your happy.
Also there are advantages to setting up with the semantic system, you may want to use this and model your home as intended which means going back to scratch in some areas.
I don’t use sitemaps, only HABPanel. Don’t recall rules or bindings config referencing static openhab2 directory. If these are the only issues then there’s probably no issues.
I did try using a fresh installation but the guide above mentions that configs are only copied/migrated automatically if they were already present on a OH2 system during installation phase.
Dunno about that, but it’s probably because you changed from the v1 binding to a v2 one as you need to use in OH3.
That in turn is not an OH3 breaking changing, has nothing to do with that in fact as you could have moved already in OH2 at any time .
Question on OpenHAB 3, has a solution for expire binding been found? I am unsure if it converted or was obsoleted. I think this is my only tricky part for me to move oh3 to production.
There is a discussion on this in git hub https://github.com/openhab/openhab-core/issues/1620. As far as in understand the Binding is obsolete, but the new functionality is under development and should be compatible to the binding