I worked in a lab where we had a computer dedicated to running a very specialized piece of equipment. The computer was a 386 running DOS. We had all of the software updates (including operating system) to upgrade everything if needed in case the computer stopped working. That was only a few years ago, and as far as I know that 386 is still running. After seeing the current software for running that piece of equipment, I understand why the lab never upgraded. The old UI was a bit clunky, but it was much easier to use.