From MaGog's logs for 26 April:

NOTE! Probably ADDED FILE Grim Dawn, all_files, DLC: Pre-Kickstarter Legendary DLC: Windows installer, English, dl_ver: ***TO*** gog-5





NOTE! Probably REMOVED FILE Walking Dead: Michonne - A Telltale Miniseries, The, all_files, Windows installer, English (part 1/2 of 2) (dl_ver: gog-4)

NOTE! Probably ADDED FILE Walking Dead: Michonne - A Telltale Miniseries, The, all_files, Windows installer, English (part 1/2/3 of 3), dl_ver: ***TO*** gog-5

NOTE! Probably ADDED FILE Walking Dead: Michonne - A Telltale Miniseries, The, all_files, Patch gog-5 (episode 3) [Windows], dl_ver: ***TO*** gog-4 -> gog-5

NOTE! CHANGED Walking Dead: Michonne - A Telltale Miniseries, The, changelog (http://www.an-ovel.com/downloads/chg/chg_1455785261.htm)
NOTE! ADD +++ Patch gog-5 (26th April 2016)
NOTE! ADD +++ This update adds Episode 3

NOTE! CHANGED Walking Dead: Michonne - A Telltale Miniseries, The, file_size: 3.5 GB ***TO*** 5.4 GB





NOTE! CHANGED Big Pharma: Marketing and Malpractice [DLC], languages: Audio and text: English. Text only: German, Spanish, French, Polish ***TO*** Audio and text: English. Text only: German, Spanish, French





NOTE! CHANGED Divinity: Original Sin - Enhanced Edition, languages: Audio and text: English. Text only: German, Spanish, French, Italian, Polish, Russian ***TO*** Audio and text: English. Text only: Czech, German, Spanish, French, Italian, Polish, Russian

[Same for Collector's Edition]

NOTE! CHANGED Divinity: Original Sin - Enhanced Edition Collector's Edition [Premium], os: Windows (7, 8, 10) and Mac OS X (10.9.5 or newer) and Linux (Ubuntu 14.04, Ubuntu 16.04) ***TO*** Windows (XP, Vista, 7, 8, 10)

[Probably a GOG page bug]

From MaGog's logs for 26 April:

NOTE! CHANGED Divinity: Original Sin - Enhanced Edition Collector's Edition [Premium], os: Windows (XP, Vista, 7, 8, 10) ***TO*** Windows (XP, Vista, 7, 8, 10) and Mac OS X (10.9.5 or newer) and Linux (Ubuntu 14.04, Ubuntu 16.04)

[Still doesn't look right. The regular D:OS EE does not list XP and Vista, while the Collector's Edition now does. One of them is likely wrong.]

no kickstarter DLC for me (Grim Dawn)

DLC: Pre-Kickstarter Legendary DLC: from Grim Dawn

i assume im a good enough customer, with all the games i bought :) No T-Shirt either with what i heard other top GOG buyers got :(

Pretty sure it's the Collector's Edition that's wrong.

Divinity: Original Sin - Enhanced Edition has just received a manual.

Oh, so it actually replaced the previous one.

Got a flag for Darkest Dungeon.

Windows:

I can download the patch 2.12.0.16 for Windows, but get 404 Error for downloading the full game for Windows.

Grim Dawn has 12 kickstarter-type DLCs. They are no for sale and they are not free. You get a code for one or more of them only if you backed the game on Kickstarter. The one added yesterday is just one of these twelve.

It works now, thank you Judas.