Apple devices that are running iOS 10 or macOS Sierra no longer meet the minimum system requirements for iCloud, according to Apple's updated iCloud support document.All iCloud features now require iOS 11 or macOS High Sierra at minimum.iCloud services like Keychain, iCloud Photos, iCloud backups, Find My, and iCloud Drive will no longer work on devices that are running iOS 10 or macOS Sierra.
iOS 10 and macOS Sierra launched in September 2016, which means the updates are now nine years old.iOS 10 was the final version of iOS available for the iPhone 5 (2012) and the iPhone 5c (2013), along with the fourth-generation iPad (2012).These devices will no longer be able to access iCloud services.
macOS High Sierra was compatible with all Macs running macOS Sierra, so there are no Macs that are losing iCloud support with the compatibility change unless those Macs have not been updated to the last version of macOS they support.
