Rocket League will have an update on Feb 21. that allows it to support a 4K resolution and 60 frames per second on PS4 Pro.
There is one caveat: three or four player modes won’t hit 4K, but they should still run at 60 fps. With that said, Psyonix can’t guarantee that frame rate for every arena.
This comes on the heels of the PS4’s 4.50 system update, which boosts the performance of older PS4 titles on PS4 Pro. Rocket League will be one of many previously released PS4 titles to get an upgraded resolution and frame rate.