I previously had to downgrade my Mac OS to Catalina (10.15) and was using Parallels 15 in order to maintain use of legacy software. However, I then upgraded to macOS Big Sur (11.7) and installed Parallels 16. When trying to use my previously purchased permanent Parallels 16 activation key (i.e., non-subscription license) for software activation, it says that I need to input "a key from a previous version" since the one for Parallels 16 is an upgrade license. And so I did, since I also have two permanent licenses from previous Parallels versions (13 and 15). However, neither of them worked, leading to an error prompt that says, "The previous activation key has not been accepted by the license server." I have purchased three permanent activation keys for previous Parallels versions (13, 15, and 16) and am trying to activate Parallels 16 on my macOS Big Sur (11.7) laptop. However, an error keeps popping up not allowing me to do so. Is there any way to fix this?