The Y10K problem is similar to the
Y2K problem in that it is the inevitable violation of a common implicit assumption in software design, albeit one significantly less urgent. When December 31st, 9999 changes to January 1, 10000, the year will become 5 digits long. A good deal of current software is not able to display 5-digit years and will need to be updated to deal with dates generated past this moment (Assuming, of course, that the
Gregorian calendar is still in use, or indeed that there will be anyone left to mark the passage of time.)
The Y10K problem is typically brought up in a discussion to imply that the concept of
planning for the future has been taken to a ludicrous extreme well past the
point of diminishing returns.