Apple will be dropping support for iCloud for macOS Sierra and iOS 10, with all features for iCloud now requiring macOS High Sierra or iOS 11.
macOS Sierra and iOS 10 are no longer eligible nor match the minimum system requirements of iCloud. The macOS Sierra and iOS 10 were released 9 years ago in September. iOS 10 was the last version for the iOS used in the iPhone 5, 4th gen iPad and iPhone 5c, meaning that these gadgets will also not be able to access the services iCloud offers.
iCloud offers secure services that can be synced across your Apple devices like Find My, iCloud Photos, Keychain, iCloud Drive and iCloud backups. All macs that have macOS Sierra are eligible for the macOS High Sierra, meaning no Mac will be losing support from iCloud. Once you update to the latest version, you can still use these features offered by iCloud.
