I saw on the steam forums someone posted a video showing ultrawide suppport, but for some reason I can't put it in 3440x1440 any ideas why?

Thanks

Apparently the early build or the review build had it, and updates removed the feature.

Currently on GOG build 1.02. I use a mod found on pcgamingwiki and now i can play the game at 5760x1080 :) maybe you can use the same mod to play ultrawide. It's a file which will patch "globalgamemanagers" on the game folder.
I hope my comment can help players.

Je suis sur la version GOG 1.02. J'utilise sur pcgamingwiki un .exe qui patch "globalgamemanagers" dans le dossier du jeu pour forcer le jeu à la résolution de l'écran. Je peux jouer en 5760x1080.
Peut-être que cela fonctionnera en 21:9. En espérant que mon commentaire aidera d'autres joueurs.

ht tps: // ibb.co/ f2T5Cp0

i7-8700k OC 5.1Ghz (All cores)
1080Ti OC 2038Mhz
32 Gb RAM OC 3200Mhz
2To SSD
Windows 10 - 1909 - 18363.535
5760x1080