Year 10000: the four-digit calendar has company

A format can be perfectly useful over its intended range and need a revision beyond it. RFC 3339 defines a four-digit year in its timestamp grammar. Year 10000 exceeds that particular field width.

The problem is about assumptions carried into data formats. It is not a reason to expect every computer to overflow at once, and it should not be confused with a signed Unix time counter. Those are different mechanisms, with different repair work.