Including various advances and additions in the technology and mechanical sides of things that are too numerous to list, we'll focus on the most obvious change, the redesigned hood.
The VAH is basically a VHD with low profile parts such as roof and suspension components.
That said, it shares its hood with the new VHD.
The hood's most obvious new design feature is the headlights, which are drastically different from the previous iteration. The photo above shows the new lights, and the photo below shows the old:
In my opinion, the new lights are not an upgrade.
I can't quite put my finger on why, but I think it's more the shape than the actual interior design of the light. It seems too rectangular, whereas you expect Volvo to be a little more fluid in their design features.
The new VNLs for example have nice looking headlights that are a significant improvement over the old ones.