The ability to retract sent messages is built into iOS. Before this feature debuted, several known workarounds were discussed to try and prevent an iMessage from being sent. Most of these are not practical after the Send button is tapped. Fortunately for anyone looking to unsend a message, Apple provides an easy way to delete sent messages from the recipient's device.
Most of the focus lately has been on iOS 16, Apple's latest iPhone operating system. Apple has also provided an important security update to iOS 15. This means that Apple has released two updates side-by-side, iOS 15.7 and iOS 16. iPhone owners can elect to install the iOS 15.7 patch or do a full upgrade to iOS 16.
Every year there are some iPhone models that can't support the latest version of iOS. While Apple supports hardware for many years, at some point there are limitations preventing an update.
iOS 16 cannot be installed on the iPhone 7 and earlier. This means that the iPhone 7, iPhone 6s, and original iPhone SE (1st generation) are stuck on iOS 15.
Apple has moved to eSIM only for US customers. This means the iPhone 14, iPhone 14 Plus, iPhone 14 Pro, and iPhone 14 Pro Max do not include a physical SIM card tray.
With the iPhone 14 lineup, Apple has fully transitioned to eSIM technology for US customers. This means US models of the iPhone 14, iPhone 14 Plus, iPhone 14 Pro, and iPhone 14 Pro Max do not include a physical SIM card tray.