Not even 2.1k, because of the 2 digit years, they'll fail before that even. They've usually got some kind of cut off date where before that it'll give the wron

Not even 2.1k, because of the 2 digit years, they'll fail before that even. They've usually got some kind of cut off date where before that it'll give the wrong Day of the Week because it's using the wrong table now.