In the last PS3 update, 4.10, you could use a feature that let you hear your own voice through your wireless headset. This is called sidetone, and while it is useful in multiplayer mode, it needed a bit of tweaking. This is what the update tomorrow aims to do.
The PlayStation Blog stated:
Based on your comments, system software update (v4.20) will improve sidetone audio performance by giving you the option to select one out of five levels for microphone audio, or turn the feature off completely. For those of you who use the Wireless Stereo Headset to watch Blu-ray or DVD movies on your PS3, this system software update will also enable virtual surround sound functionality…
In addition to this, you will also be able to group saved data for copying or deleting. This is quite helpful as it cuts out having to deal with the arduous task of filing through each and every one of them. Lastly, you will be able to set the amount of time your system will wait before it shuts itself off.