You’re going to have to upgrade your devices or find a workaround eventually.
Beginning in December, Apple will require users performing a backup over iCloud to be running iOS 9 or later. Per an email to its customers, Apple stated that new backups for iPhones and iPads running iOS 8 or earlier will no longer be supported, and Apple will delete all existing iCloud backups of those devices as well.
Apps and data stored on an iPhone or iPad running iOS 8 or earlier will not be affected, and Apple says that customers can still manually back up their devices to a Mac or a Windows PC.
These iCloud backup changes will go into effect on December 18, 2024, and customers running iOS 8 or later should update their devices to the most recent version of iOS that’s compatible with their hardware in order to be able to back up to iCloud.
According to Apple, iCloud backups for older devices are being discontinued in order to “more closely align” with Apple’s “published minimum software requirements.” With iOS 9, Apple adopted CloudKit for iCloud backups rather than the prior system, and it seems that the company is now discontinuing the old backup system.
Stay tuned for additional details as they become available.
Via MacRumors and @nicolas09F9