Backing up your device via iCloud now requires iOS 9 or later, which means iPhones and iPads running iOS 8 or earlier will no longer be able to back up via iCloud.
Apple announced this change earlier, and now it’s officially in effect. Support for iCloud backups on devices running iOS 8 or earlier has ended, and Apple has also deleted all existing iCloud backups from those devices.
Data and apps stored on iPhone or iPad running iOS 8 or earlier will not be affected.
Users can still manually back up these devices to a Mac or Windows PC. For devices still running iOS 8 or earlier, if you can upgrade to a newer version, you'll restore iCloud backups. If you can't update, all backups will need to be done manually.
Apple says it's ending support for iCloud on older devices to "more closely align" with its minimum software requirements.