Another concern with Y2K is a little-known fact, that anything that uses 32-bit integers to save time will wrap to 1902 on January 4, 2038. This is called the Y2K38 bug.
It's a little-known fact, but it's a real concern, because anybody who bought a legacy system up to maybe 10 years ago and is still using it at the end of the 2030s—which will happen, I guarantee you—will have this perverse problem. We're not finished with the Y2K bug quite yet.