Nice hope the devs continue to support their releases on GOG!

This game has been on my backlog for ages... Maybe it's time to give it a try

Great! I bought it relatively recently, but have been holding back with playing it since I heard about the huge update. Time to get to it, I guess.

How do we notice the major update? Just started the game and there ain't no clue, that's telling me, I would actually play the enhanced edition oO
Main menu is still the same, no hint here. I loaded a savegame, also nothing telling me anything about any changes since the last time I played (back in 2020) ... just wondering, if THIS are the changes... and if not, why the game then is not already updated. I installed via galaxy...

Only the Windows installer has been updated. Mac and Linux are still stuck in 2019. Might consider buying if the update is here before the discount is over.

Great news! And then - bad news. (negates the good news for me)

According to gogdb, Windows is version 1.6.24, Mac is 1.5.35, and Linux is 1.4.39. According to steamdb, Mac and Linux were last updated in 2020. So if Mac/Linux is out of date even on Steam, I wouldn't expect them to ever be updated on GOG. At this point it would probably be better if the store page didn't list Mac and Linux versions at all.

Dumb question, but don't most Linux user just use the windows version on wine or proton?

If all else fails (native build) - yes. Me, personally, prefers native over wined, see below:

Using vanilla Wine/Proton adds an overhead (~ 0.5 GB prefix, could be ~ 1GB nowdays?) and dependency to tools that might or might not have regressions as they evolve on their own (yet another overhead if your library includes a bunch of titles).
Having said that, I'm very, very pleased by the quality of vanilla Wine for the past ~ two years. Don't have the data but it seems Devs bother no more to provide native builds because of the improved quality of Wine/Proton in the last couple of years. Think Steam Deck and Valve's Proton efforts are to be blamed here. Anyway, native or not (and what it means for Linux gaming) becomes a purists' debate. Think the average Linux player (esp. Steam Deck's) pays attention no more...