Ah, brings me back to decades ago when we sold and supported custom DOS apps - we would force the installers to change the time of the .EXE file to match the in

Ah, brings me back to decades ago when we sold and supported custom DOS apps - we would force the installers to change the time of the .EXE file to match the installed version number, e.g. 01:00 am for version 1.0, 01:13am for version 1.13 etc. That way we thought we could tell which version the user was using over the phone by asking them to do a DIR (useful if they couldn't start the application to see the version number in there). Of course, this system rapidly broke down because users would copy the files across to different floppies or hard drives, causing the file dates to be reset to whatever it was at the time!