PSBlog - "Later today, the next system software update for PlayStation 4 (version 1.51) will be available. With this minor required update, stability of system software has been improved. In addition, 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) have been introduced.
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."