Huh there is new battle mechanics btw what happens if I unlocked all the girls already will I have to do their war fights again to see the new things?
Yep, old progression in the battle system is no longer valid.
But not everything has been re-implemented yet, and the new system is a bit rough around the edges.
I’d say wait for 0.20.0
You do need to do the fights again, but fortunately it's just six this time - districts have been removed in favour of locations and each girl only needs to be defeated once to conquer the area :)