iOS 13, iOS 14, and iOS 15 all supported the same list ... A9/A9X chips or older starting next year. This includes the iPhone 6s series, the 1st-gen iPhone SE, and several old iPads.
Meanwhile, in the second beta of iOS 14.4, Apple is introducing a new warning on iPhones that have had their camera repaired or replaced with aftermarket components rather than the genuine Apple ...
14, and 15 supported the same phones. When WhatsApp drops support for iOS 15, however, it will lose five more phones: the iPhone 6s and 6s Plus, iPhone 7 and 7 Plus, and the original iPhone SE.