Like clockwork, a new mandatory PS3 system software update has appeared! One month after the release of firmware 3.73 comes the big four point zero.

The update, which went live last night, is largely meant to prepare the system "for the launch of PlayStation Vita in Japan," allowing the console to connect with Sony's new portable in a variety of ways. For example, the update will allow you to copy content, such as games, music, photos, and videos, between the PS Vita and PS3.

Much of the cross-platform functionality is similar to that of the PS3 and PSP. You'll also be able to copy Vita save data and set up Remote Play. New to the Vita is the ability to update the firmware of the Vita using "the network features of your PS3."

In addition to Vita support, 4.00 also tweaks the automatic update feature for PlayStation Plus members, giving them granular control over specific update features. In addition, there are new PlayStation Network settings for filtering friend requests and messages.

While 4.00 may not revolutionize the PS3 experience, it's still a mandatory download. Once Vita comes out in February, we may think differently, though.