iOS 17 and iPadOS 17 will be incompatible with most devices running the A11 Bionic chip and older. The only exceptions will be the 6th generation and 7th generation iPad models with the A10 Fusion chip, the 12.9-inch iPad Pro with the A10X Fusion chip, and the 2nd generation 10.5-inch iPad.
Last year, the iPhone 6s, iPhone 6s Plus, iPhone 7, iPhone 7 Plus, 1st generation iPhone SE, recent iPod Touch models were excluded from the iOS 16 update.
When will iOS 17 be introduced?
Apple will reveal iOS 17 features at the WWDC event on June 5. After iOS 17 innovations are transferred, the iOS 17 beta version (for developers) will be released soon.