The PlayStation Portable system software is the official firmware for the PlayStation Portable. It uses the XrossMediaBar (XMB) as its user interface, similar to the PlayStation 3 console. Updates add new functionality as well as security patches to prevent unsigned code from being executed on the system. Updates can be obtained in four ways: The current version of the software, 6.61, was made available on January 15, 2015. It is a minor update released more than three years after the release of the previous version 6.60 in 2011.