OpenAPRS for iPhone 2.3.1 has been released!

Included in this release:

• Push notification support
  
• Memory improvements
• Local storage of APRS messages
• Background support (including background beaconing support)
• FCC callsign lookup
• Improved signup and account tools
  

You will need to make sure your device is running iOS 4.2 or higher in order to get this update.