If this rumor is accurate, iOS 17 and iPadOS 17 would be incompatible with most devices powered by the A11 Bionic chip or older. The only exceptions would be the sixth-generation and seventh-generation iPad models with the A10 Fusion chip and the second-generation 10.5-inch and 12.9-inch iPad Pro with the A10X Fusion chip.
iPhones and iPads equipped with the A5 through A11 chip are affected by a bootrom security vulnerability that Apple cannot patch on these devices, as the bootrom operates in a read-only state. The exploit has allowed for these devices to be perpetually jailbroken on a wide range of iOS versions, allowing users to modify the iOS file system.