Patch 1.10+ introduced major changes to save files. By 1.13c/d and 1.14d, the structure is mostly stable but has subtle differences:
: Traditionally stored within the game's installation folder (e.g., C:\Program Files (x86)\Diablo II\save ).
D2R blocks certain modded items and has its own anti-tamper. For pure single-player, though, your 20-year-old patched Sorceress can live on in 4K glory.