A few hours ago, Sony started pushing PS4 Firmware 5.53.
As always with minor updates, details on what the update actually does are very sparse. Most mainstream media just quote the official changelog which is the usual “This system software update improves system performance”, although some say the update could be related to the upcoming God Of War release. The game is getting great reviews and it is possible Sony want it to perform as best as possible on launch day.
PS4 5.53 and Data/Privacy
Firmware 5.53 is now giving you more options to choose how much data you want them to collect from your console. This includes data about online services (which cannot be deactivated), and navigation data (how you use the console. That part can be turned off). In general, my personal recommendation would be to share as little data as possible, independently of your use case.
Downgrade from 5.53 to 1.76, 4.05 and 4.55 will release soon.