A while back I found a game from 1993 which I pulled off floppy disk. It is a 16-bit executable that was originally designed for Win 3.1.
To my surprise, it runs fine on (32-bit) Windows 10. With sound and everything.
I have Mac applications from three years ago that will not run on the current macOS.
I have Linux applications that broke and/or became crashy during a routine system update which updated some libraries and required a recompile to restore stability.