WhatsApp will drop support for iOS 10 and iOS 11, requiring Apple users to run at least iOS 12 on their iPhone after October 24, 2022. This will mainly affect iPhone 5 and iPhone 5C owners, which are the devices still running iOS 10 and iOS 11.
This means that iOS 10 and iOS 11 users will no longer be able to use the encrypted messaging services after the October 24 date.
WhatsApp tells users on its Help Center that it currently provides official support for iOS 12 or newer, so it looks as if iPhone models like the iPhone 5s, iPhone 6, and iPhone 6s will remain fully supported for the foreseeable future.
Users will need to upgrade to newer iPhones if they want to continue to use the service. Users who are upgrading can back up their WhatsApp chats to iCloud for restoration to a newer, supported device.