iOS 4 saw the iPad joining the scene and using the operating system alongside the iPhone ... for iOS 15 – leaving the iPhone SE, iPhone 6s, iPhones 7 and 7 Plus vulnerable.

Surprisingly enough it was possible in this era to run an entire instance of Mac System 7 within either of these two Unix operating systems, and this was an officially supported piece of Apple ...

When your iPhone's operating system has completely cracked and is unable ... If you're using an iPhone 7, start with your iPhone on. If using an earlier model, turn off your iPhone.