By the way, it seems that some mac OS control panels don't accept dates after 2019. It will allow dates after 2019 but won't let you change it

http://web.archive.org/web/19990423125824/http://www.apple.com/about/year2000/y2kos.html

The current version of the Mac OS Date & Time control panel is Year 2000 compliant, but constrains user input to dates between January 1, 1920, and December 31, 2019. Well in advance of the year 2019, the Date & Time control panel will be revised to support future dates, using OS utilities that can handle time all the way to the year 29,940 A.D.

Click to expand...

It certainly isn't the case with system 7 but maybe with earlier systems? But it seems that some programs can change the date http://web.archive.org/web/19990503043328/http://developer.apple.com/techpubs/mac/OSUtilities/OSUtilities-95.html

Now, I don't know if programs like those exist at the time being but if they don't it would be good to have them by 2019...