Quote Originally Posted by VG247
Game producer Matthew Cederquist confirmed this to IGN Middle East, explaining that it was a happy accident and not something the team specifically wanted to have.

“Yes! Yes, keep those!” Cederquist said when asked whether years-old saves in the original will work.

“Back when we were working on [the remaster], we wondered if the old save files would work and we kind of shoved it in and it worked! And we were like, ‘okay, that’s the best feature ever’.”
Diablo 2: Resurrected will accept your 20-year-old saves from the original - VG247