A new firmware update was released yesterday, bringing the current system software to version v3.73. In order to download PS3 system software version 3.73, you will need a minimum 186MB of free space on either the PS3 Hard Disk Drive (System Update) or on removable storage media.
Depending on the software title, you may not be able to play without first updating the PS3 system software to version v3.73. The update is a minor patch that improves the playback quality of some PS3 titles.