You can update your Nokia 5800 firmware over OTA (Over-The-Air) or by using Windows PC applications like Nokia’s Software Updater or Ovi Suite . The Nokia 5800 does have UDP (User Data Preservation), but its always good idea to backup all of your personal data before updating the device firmware.
Note: There is no official changelog yet, But we will update you as soon as we get. Meanwhile if you notice some thing new after updating your Nokia 5800, tell us in your comments!
[Thanks to Dhanusaud for the lead]