Messaging app WhatsApp has recently updated its minimum software requirement for Apple devices, and is now asking for iPhones to be at least iOS 10 or older.
iOS 9 users, mainly those who use the iPhone 4 were still able to use the chat service. However, the company has ended support for it and now iOS 10 is the minimum software. The same thing happened last year when the Facebook-owned app announced that they will be dropping support for iOS 8.

Those who are interested in the details can view the support document on WhatsApp’s official website. The Help Center now lists the minimum for iOS to be iOS 10, while Android phones will have to be at least OS 4.0.3 or newer.
Users who are unable to use WhatsApp can back up their data to the iCloud platform and have it restored to a device that meets the minimum specifications.