The main durability and ease of service updates were relocating the bearings to the metal linkage from the swingarm/frame, switching to collet axles, and using more common bearing sizes. As someone who's spent a good bit of time working on Yetis I welcome these changes.
These updates definitely apply to the 'carbon' series frames, as they had to change the carbon layup and linkage shapes to relocate the bearings. If you lookup a picture of a C1 build you can see the collet axles and the changes to the links and frame.
Apparently they also made updates to the infinity link itself which are not applied to the 'carbon' series frames, as they come with a cheaper non-kashima link. This is likely what PB was referring to
I personally don't think think the updates to infinity link are as important, as most Yeti's I've worked on had issues with pivot axles/hardware rather than issues with the link (excluding the sb100). Most of the time someone did wear out their infinity link it was because they had some other pivot issue they were unaware of and kept riding. I think people focus too much on the infinity link and its "added complexity" when really it's pretty simple. This bike uses 8 pivot bearings, while my Enduro uses 20...
Not trying to defend Yeti too much, some of their past bikes had serious issues. But I think the updates to this one are a step in the right direction. Not even gonna mention price because Yeti