Harmonix has released a significant patch for Rock Band 2, which adds and fixes a swathe of features. It's out now on Xbox 360 and is apparently in certification for PlayStation 3.
Chief among them is a new Audition mode for the Rock Band Network, where users can upload songs from their PCs to try them out using the game's tools.
Background downloads and the ability to stack multiple songs will soon be reality, and the patch also enables Xbox 360 wireless microphone support.
Hammer-on and pull-offs are being improved, too, and the Ion Drum Kits will soon be velocity-sensitive. Finally, there's a Sort By Stars option coming to the Quick Play mode, so you can see which songs you have played and mastered at a glance.