With the OneDrive Backup you can save the anniversaries you have added in Birthday Hub with Add anniversary in your OneDrive. The anniversaries from the Windows Contacts app are not saved because they are already in the cloud.
Select the Data backup menu item from the main menu to open the OneDrive Backup page.
First, log in to your OneDrive using the Sign in button. The login process works via the so-called OAuth procedure.. This means that the login runs directly through Microsoft’s OneDrive or its Microsoft account and Birthday Hub does not know its login data (username and password).
If you are successfully logged in, the Backup button is enabled, and if you have already made one or more backups, they are automatically downloaded and displayed.
Press the Backup button to create a backup in your OneDrive.
To restore a backup to Birthday Hub, select an existing backup from the list that you want to restore. This enables Restore button. Then click the Restore button to restore the selected backup.
Restoring a backup will override any data created in the app. This has no effect on the imported anniversaries from the Windows Contacts app.