Backup and restore all user data so you do not lose any data when upgrading Android. Upgrade process will overwrite user data store, but if the application using Backup & Restore, you can keep all settings, messages, contacts and much more. The entire user data are stored on the memory card so you can easily recover after upgrading Android.
Make sure you have updated the latest version of the application Backup & recovery before the start. Remember to make backup process before you upgrade your Android to not lose any data!