The game has received updates until December 2023 on Steam (https://steamdb.info/app/1156380/patchnotes/) but the GOG release is lacking over an year of said updates, as the last one took place in September 2022 (https://www.gogdb.org/product/1682649193#changelog).

I know it's not rare that we don't get parity with Steam, but it shouldn't happen in first place.
I hate that I have to check what games I should buy on GOG based on how much the developers care about us here.