DigitalFoundry released its analysis of the Supersampling mode (part of the 5.50 firmware), which offers benefits to those who only have a 1080p display.
The mode makes the console effectively scales back the resolution to 1080p while having improved visuals compared to an ordinary PlayStation 4. The issue here is that several games will sometimes show significant performance drops if we have supersampling enabled!
The Last Guardian regularly had frame rate issues on a 4K display, which is still present on 1080p. However, if we disable supersampling, there is an option to natively run the game on 1080p resolution with somewhat worse graphics. The other similar game with the issue is Call of Duty: Black Ops III.
If the performance drop is too big, DigitalFoundry recommends disabling supersampling, but their analysis also points out that the firmware update, which should be public shortly, will thus allow an option for a downscale in the resolution that several games did not offer before.