After you've upgraded to iOS 7 or after you've migrated your content to a new iPhone there are a few things that you should check.
- Check your data and new backup before deleting an old backup. After migrating, check that your important photos, messages, files, and app data are available on the new iPhone. Then complete a new backup. For iCloud, go to Settings > your name > iCloud > iCloud Backup, tap Back Up Now, and stay on Wi-Fi until it finishes. Check the last backup date and time below that button. If you cannot complete a new backup, keep the old backup and resolve the storage or backup problem first. Deleting an iCloud backup is irreversible and also turns off iCloud Backup for that device. Only consider deletion after these checks, and confirm the exact old device by its name and backup details. On current iOS, go to Settings > your name > iCloud > Storage (or Manage Account Storage) > Backups. Select only the old device's backup, then use Turn Off and Delete from iCloud if you are sure you no longer need it.
- Make sure that your backups are turned on. It's worth mentioning again because sometimes after an upgrade or especially after migrating to a new iPhone this can get flipped off or it may stop working because you are out of iCloud storage space. If you need more iCloud storage try #1 and then try deleting messages or deleting some apps, though apps that have a lot of app data won't affect your storage (since those are stored in the App Store), only ones that store a lot of your own data such as documents and pictures will take up storage space.
- Turn on Find My iPhone. Make sure that this is turned on in the Settings app > iCloud. In addition to the ability to locate a lost iPhone (even override the silent switch!) it now allows you to remotely lock your iPhone so that no one can use it until you enter your own Apple ID and password. This is a huge theft deterrent that will hopefully make iPhone theft a thing of the past.
