Sony has recently revealed (via their blog) that the recently released System Software Update (1.65) for PS Vita includes the following improvements:
"A 'Notification Alert' option will be added to Settings, so you can toggle alerts on or off.
'After 10 minutes' will be added to the time options under Power Save Settings.
An Arrow icon will now appear when PS Vita finds new activities in the LiveArea.
Caps Lock will be supported in the On Screen Keyboard."
NeoGAF Forum users also added these improvements to list:
"Near updates at any time instead of every 60 mins.
Turning off notifications turns off ALL notifications including trophy pop ups.
Background downloading now works when you manually go in sleep mode.
Percentage bar when installing a game."
Updates can be performed by either using the handheld's wi-fi, or by connecting to a PC/Mac and updating via the Content Manager.