It's funny, but the OS install in the original workstation dates from late 2015 (looking through my install notes). That system has been through some major hardware and OS upgrades in the last 6 years, so my cloning it to new hardware continues the tradition.
I originally had a Core i7-6700 installed in there, with Win 8.1. In 2018 I upgraded it to a Core i7-7700 and used the old CPU in another build (the mobo supported 7th gen processors with a BIOS update). THAT wound up biting me in the ass because I hadn't realized that Win8.1 doesn't support Intel after 6th Gen (Windows refused to boot and gave me a processor compatibility error). So, not wanting to do a fresh install back then either, I did an upgrade to Win10 1803, which went smoothly (had to put the old processor back in to do it). Since then it's been upgraded to build 1909, so I'll need to upgrade the new system to 20H2.
The transplant went well last night. After running Macrium Redeploy, it gave me an MBR boot error, so I ran a utility in Macrium that clears and configures the MBR, and it booted just fine after that (this system, and the one I cloned it from is NOT running UEFI, which probably made it easier). Installed mobo drivers, and everything seems to be working fine. Burned it in with Prime95 for several hours to test stability. In the process of cloning additional partitions, and some other housekeeping, while I wait for the case to arrive.