I didn’t upgrade my final cut version, but i did switch to a Mac Pro from a G5, but was on FCP 6 on both. And When i went to the Mac Pro i kept working on 4 external hard drives with no trouble, but external drives make me paranoid so i installed some big internal drives and transfered the footage over to them and then relinked.
SO essentially nothing changed except for going from External drives to Internal drives.
But when i relinked it did say “you are linking with a new version of FCP and cannot go back” But i’ve seen that 100 times with no problem??