According to developer sources for Kotaku, Sony is currently working on a new version of the Playstation 4. According to these developers, this “Playstation 4.5” will include an upgraded GPU that will provide 4K resolution as well as more processing power for those looking to program games for Playstation VR.
Playstation 4 currently allows 4K resolution for both photos and videos, but doesn’t truly support 4K gaming as 4K’s outputs are 4096×2160 pixels. The current Playstation 4’s max resolution is 1920×1080.
Kotaku has 2 sources and 2 of their writers were able to independently verify the existance of Playstation 4.5. Sony allegidly had meetings with several developers to discuss these upgrades. There is no word yet on a release date or price of Playstation 4.5, or if it will just be upgrades you can do yourself to the current system.