PlayStation 4 Pro owners will soon get to play the excellent Rocket League in glorious 4K starting February 21. Even better, the game will still run at 60FPS for most arenas at that resolution. The PlayStation Blog has some information about what this Pro patch includes.
On February 21, we will release a new update that allows Rocket League to run at both 1080p (on a standard PS4) and 4K (on PS4 Pro) at 60 frames per second in all arenas for single and two-player split-screen modes. Three and four-player split-screen modes will offer 60 frames per second in most arenas at the same resolutions.

In addition to the new visual optimizations we’re making, our next update will also bring…
• Hot Wheels premium DLC cars, Twin Mill III and Bone Shaker (sold separately).
• Additional free Hot Wheels-themed post-match item drops, including both Toppers and Antennas.
• A new fan-voted “Player’s Choice” Crate filled with some of the community’s favorite items.
• PS4-specific technical improvements.
• Multiple performance optimizations and bug fixes.

Psyonix continues on to say that this is the first of many planned content updates that they have in store for Rocket League throughout 2017.