I did the same (upgrade from Catalina) and had no problems. I only bought an Apple Silicon MacBook because the mid-2012's hinge got too loose to keep the displa

I did the same (upgrade from Catalina) and had no problems. I only bought an Apple Silicon MacBook because the mid-2012's hinge got too loose to keep the display upright. Yes, the new computer is significantly faster, but I could have lived with the older one. So, three cheers for OCLP! PS - the mid-2012 is now a backup, so is still useful.