How do I get it?
Or at least the Build #16628 that was released on Steam last week.

Totally agree with you. 3 months since the last update is an evidence of GOG's laziness when talking about updates.

Well to be fair, Red Hook hasn't done an official update for the PC version since September. Up to now all their focus has been on the PS4 and Vita editions, which had some content exclusivity. This latest build is meant to bring the PC version in line with the other versions, but for whatever reason, GOG notably lags behind Steam in making the new builds available.

I've also seen reports that this new build has been breaking the game for a lot of players, so much so that Red Hook has given Steam players the option of rolling back to the last stable build. I'm wondering how this will affect us GOG players...

Someone contacted me on a reddit post I did few days ago.

https://www.reddit.com/r/darkestdungeon/comments/5jz110/gog_owner_worried_about_the_updates/

"We uploaded it so it should be switched over soon. Sorry for the delay!"

It seems it's someone from redhook, "Redhookjohn".

Hope to have it before the end of the month...

Indeed. Tyler Sigman from Red Hook responded to me on Twitter about this. Said they gave GOG the green light to make the new build available but that the holiday might have fouled up the timing. Theoretically it should be up any day now.

Big ups to both of you for letting us know. I was super sad face.