Hi, I have multiple ios devices, my girl friend also.
I have one roon server, installed in one main househould. We have a 2.nd household (for vacation), no roon server installed.
We use ARC for mobile use and in our 2nd household. How many ARC devices are legally supported?
Any number, as far as we know. If there was some limit, surely it would say so when one too many instances of ARC gets connected to the server.
Of course, all of them need your personal Roon login, which should create a natural limit to who you share it with.
Licensing is matched to the Roon server instance; the number of connected remotes/ARC/endpoints is unlimited.