While all iPhones that can run iOS 17 are also compatible with iOS 18, you have to make compromises with iPads
The first rumours that Apple would exclude several iPads from the update to iPadOS 18 were already circulating in winter 2024.
Tipster @aaronp613 correctly predicted that the second-generation iPad Pro 12.9-inch and the iPad Pro 10.5-inch would disappear from the compatibility list.
Apple introduced both devices in 2017 and both feature the A10X processor. The A10 processor has long since disappeared from the iOS compatibility list; the iPhone 7 with this chip last received the latest system in autumn 2021 with iOS 15, with iOS 16 being the end of the line.
However, there are still two models in the iPad range that have this chip on the motherboard: the sixth-generation iPad and the seventh-generation iPad.
