The point-of-sale terminals have vendors that produce them in large quantity and they should have the expertise to upgrade the software of the machines that they built.
One can always hire experts with a proven track record to help with the install of the new OS.
Incidentally, many people may have trouble with upgrades to the new OS because
1. Running old hardware
2. Not running quality hardware -- e.g. for Windows laptops traditionally Thinkpads.
3. Do a fresh install. E.g. don't upgrade, but backup the data, clean the disk, do a fresh install.
I use Mac and did the fresh install of Sierra 10.12.1 and then upgrades for point version updates.
I also have been running Windows under Parallels and on Thinkpads prior to 2011 and not had problems with new versions of Windows.
One can always hire experts with a proven track record to help with the install of the new OS.
Incidentally, many people may have trouble with upgrades to the new OS because 1. Running old hardware 2. Not running quality hardware -- e.g. for Windows laptops traditionally Thinkpads. 3. Do a fresh install. E.g. don't upgrade, but backup the data, clean the disk, do a fresh install.
I use Mac and did the fresh install of Sierra 10.12.1 and then upgrades for point version updates.
I also have been running Windows under Parallels and on Thinkpads prior to 2011 and not had problems with new versions of Windows.