I suspect the sync function in Finder will still work - for iOS 15, and macOS older than Catalina, I presume the sync still works with iTunes, given Apple's documentation doesn't state otherwise (or impose limitations).
I suspect the sync function in Finder will still work - for iOS 15, and macOS older than Catalina, I presume the sync still works with iTunes, given Apple's documentation doesn't state otherwise (or impose limitations).
The question asked by the OP was not that unreasonable. I suspect Mountain Lion would not allow syncing between an ios device and that Mac. So the question is really where is the line drawn?