What was changed with the hairs was a fix that allowed the hairs to no longer clip when putting on helmets and hoods. Some hairs didn't suffer this issue but materials of the hair weren't working properly. The hair is the same color but now the specularity maps of the hairs are working giving the hairs a light shine thus allowing the normal (bump) maps to work as intended. The material that was injected into hairs was necessary to be usable in the future.
No tint maps were changed and the tints always allowed for tri color change meaning that all three hair channels for these hairs control the hair to allow for various colors. This is an example of what a current tint map looks like.
as it appears just green and red, there are hints of blue in the gradient that allow for the hair highlight option to influence.
You can always use the addon mentioned AgentOrange to try and achieve the same effect.
TLDR: The hairs were fixed to allow the hairs to shine (show specularity) as originally intended. The hair is still black, just the light reflects off of it a little more making it seem less black
