I worked hard on y2k issues in 1998-1999. It was a real thing for my company at the time. It was a crisis averted. In the 80’s and 90’s I worked on many systems where the equivalent of “max date” or “end of time” was expressed as 12/31/99. The way that these systems expressed, stored, entered, and validated dates all had to be reworked in a series of major overhauls.