PG-13 (in the US), No surpise since that is what PJ had to get.
But here are the disclaimers
FOTR: Epic battle sequences and some scary images
TT: Epic battle sequences and scary images
ROTK: Intense epic battle sequences and frightening images
So the battles are now intense and epic instead of just epic (no surpise)
And the images have gone from “some scary” to “scary” to “frightening”