An update to the system software for PlayStation 4 systems was released on April 12th, 2018. You can use this to update your system software to version 5.53.
Always update your PS4 system to the latest version of the system software. By updating, you can enjoy additional features, improved usability, and enhanced security.
The system software of the PS4 system and system software updates installed on your system are subject to a limited license from Sony Interactive Entertainment Inc. Visit https://doc.dl.playstation.net/doc/ps4-eula/ for details.