If I start BOUT2 I see a launcher with the message, that the game is not up to date. What is going on?

It's a nasty DRM. Yes! GOG.com sells a game with DRM (of some kind). It connects with developer/producer(?) and downloads "latest" patches.

This updater is a hilarious joke. It runs as a service not a program. I've got SSD as system (C) drive and HDD for users' profiles and archive (D). And BACKUP! Installing BouT2 disabled my backup (witch is essential; two weeks ago it "saved my life"). MS Windows will not use any drive where are program that runs services. Some games I've installed on D because they don't need faster SSD (like e.g. The Witcher games).

Devs! It's wrong to run updater via system services. GOG.com! It's wrong to sell games with any kind of DRM when you're claiming all games here are DRM-Free. Don't do this again. Never ever.

:-/

Why GOG don't upload the current version?

IMHO questions should be: "Why developer provides online updater instead of offline patches?" and "Why developer doesn't provide latest (fully patched) installer?".

AFAIK It's not GOG.com idea with "online updater" but they shouldn't allow such game here. Shame on you GOGers...!

Is this the same on Steam? Does anyone play the game on Steam?

PS: The labels "King Art", "JoWood" and "Nordic Games" are synonyms for bad support. I think they are not interested in the problems of their customers...

I bought the the game on sale and hit a bug that won't let me progress (with the bird on the barrel) Didn't update before I started playing..but now when I try to update/patch, it fails consistently at 90%. Any ideas?

I think this is a job for the GOG support. I can not understand why gog offers unpatched games. I have the same problem to download the update like BluesyTB