Update: Sony has now removed PS Vita update v1.65 from PlayStation Network due to a technical fault related to adhoc play in PSP titles.
To quote: Hi, everyone. The next PS Vita System Software Update (v1.65) will be released soon and will include the following minor enhancements:
• 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