Apple is often praised for how fast and how consistent it is in updating its iPhones to the latest versions of iOS. Considering it only has a few models and has complete control, it's not that unfeasible. But even Apple has limits and all iPhones have an "expiration" date. For the iPhone 5S, that should have been last year with the release of iOS 11. Now it seems, however, that there's a small chance that it could actually see an iOS 12 update later this year.