Sony has just released Playstation 4 firmware 1.51. Its a minor update but a mandatory one and as per the details revealed by Sony it improves stability of system software and also add minor refinements to elements of the system UI (such as clearly indicating when a user downloads a game and a game patch at the same time).
You can download PS4 Firmware 1.51 From HERE.
In the North American region, automatic downloads for system and game updates are enabled by default when PS4 is in stand-by mode. Once system software update 1.51 is available later tonight, your PS4 will automatically download it, enabling you to update quickly and easily.