WhatsApp may stop working on these iPhones

Instant messaging app WhatsApp may reportedly drop support for Apple iPhones running on iOS 9. “WhatsApp Messenger beta 2.21.50 drops the support for iOS 9,” claims WABetaInfo, the website that tracks upcoming changes and features of WhatsApp, in a tweet.
WABeta claims that the iOS 2.21.50.11 beta version of the app no longer supports iPhones running on iOS 9. This means that WhatsApp will run on iPhones running on iOS 10 and above. This means that owners of iPhone a 4 and iPhone 4s will no longer be able to use WhatsApp.
Please note that WhatsApp has so far not updated its FAQ page that shows the list of supported operating systems. WABeta report too says that the page is still to be updated.