There is usually a day or so wait between updates compared to Steam as GOG does the updates manually whereas Steam is fully automated. GOG reasoning for this is to provide better quality support. Also there's a unlikely situation where the developer hasn't uploaded the new version to GOG because it costs money to do so everytime. A few games have done this in the past much to the frustration of gamers.

I was wondering that as well! Thanks EarthNine for the informative response.
I fail to see how the manual method ensures better quality. Does that mean the GoG team tests the update before releasing it?
Charging money to upload an update? Sorry, but that seems silly. A great way indeed to put off developers.
I really like the GoG philosophy but it still has miles to go to deliver as much as Steam.

They said in the past that offline installers have to be packaged manually, so that would explain some of the delay. Of course I understand this when there's manual work involved, but as I'm primarily a Galaxy user I expect to receive the updates as soon as possible (i.e. same day as the release on Steam). I think he meant that it costs the developer's time when they have to upload a separate build to GOG. I agree and think it's unacceptable. I really wish - and as a customer expect - that this will change for the better. But I have yet to see a blue account acknowledge the problem. Had similar discussions over at the Darkest Dungeon and Expeditions: Viking forums, where patches got delayed for days although they had just released a major DLC or the game with game-breaking bugs, respectively. The same can be observed here where the release was only some weeks ago and many people are still hyped to play. The whole situation is just sad.

Thanks for the answer, let's wait and see...