I'm not sure anything is quite as infuriating as when Bethesda puts out some tiny, imperceptible point update for Skyrim that doesn't seem to do anything but break half of your mods. So I appreciate that CD Projekt Red has taken the time to poke at some of The Witcher 3's most popular mods to discover which of them will play nice with the game's upcoming next-gen update (opens in new tab). Rest easy, folks: The game's many lustrous hair tweaks all seem to be in working order.
CDPR has put together a spreadsheet of 71 popular Witcher 3 tweaks and mods (opens in new tab) to find out whether they still function with the game's next-gen patch. The good news is that a lot of the quality of life stuff—the little tweaks that lots of players have gotten used to and would struggle without—seems to work just fine. Fast Travel Anywhere (opens in new tab), Weight Limit Removal (opens in new tab), and that mod that puts all your objectives on the map (opens in new tab) all survived the transition intact.
Where mods are broken, it's mostly due to scripting errors. In a forum post (opens in new tab) accompanying the spreadsheet, CDPR staff say that "due to the addition of a new quest [in the next-gen update], most of the mods that are based on scripts will error out". So stuff like the charmingly-named Ultra Gore 2—A Dismemberment Mod (opens in new tab) and Improved Sign Effects (opens in new tab) won't work until their authors update them for the next-gen patch. On the other hand, maybe it's a good thing: No Time for Gwent (opens in new tab) has also been broken by the update, and everybody should have time for Gwent.
On the plus side, CDPR is putting a "team of modding experts" at modders' disposal, ready to "provide help and advice to modders on forums post-release when possible". The company is also putting out "a new version of the Witcher 3 command line tools for modders [...] adapted for the updated game with many bug fixes included," and a new version of the TW3 WolvenKit mod editor/creator (opens in new tab) is set for release in the near future.
So hopefully it's just a matter of growing pains, and before too long all the mods you've come to love will be adapted to work with The Witcher 3's newer, shinier version. Until then, you'll have to tide yourselves over with mods that don't affect scripting and the ones that CDPR has gone and integrated into the update wholesale (opens in new tab). As for the authors of the integrated mods? CDPR has "obtained permissions from their creators, reimbursed them, and they’ll be featured in the credits of the updated game". Not bad for witcher's work.