Since the update "escape from the castle" is build 1359, and the mac version of Shadwen here is still 1319 I suggest you to wait for an update.
I contacted both gog and frozenbyte support with screenshot (I downloaded the game several times because they both think it is updated), but this time I show them many screenshot with both the installer/version of the game dowloaded by me on gog (shadwen_2.2.0.3.pkg) and the build in-game:
http://i.imgur.com/GetpFWZ.jpg
I write here too because they asked me to download it several times so that you can save time if you use mac gog version.

EDIT. they updated it