Sony has released a new firmware update for the PlayStation 4, advancing the system software to version v12.52. The update is a minor one and includes some security fixes for the system software.
Users must install this mandatory firmware update to access the PlayStation Network, including online gameplay and the PlayStation Store.

PS4 Firmware 12.52 Release Notes:
- We’ve made some security fixes to the system software.
You can find the official PS4 firmware update details on the PlayStation support website. See the full PS4 Firmware history here.