I was trying to help my in-laws with migrating from iOS 1Password 3 to 1Password 4. The one-time migrate screen had come and gone. I read about backing up the data, deleting 1Password 3, and then set that side up again to initiate the 1Password 4 migration. All was going well until I realized, much to my dread, that 1Password 3 is no longer available from the App Store. So, I have a backup file, but no way to access it. What should I do here?