iPhone 5s may support iOS 12, which will be presented in June of this year. To such conclusion experts from the portal MacGeneration, who discovered mention of the smartphone in the test logs of WebKit.
It is reported that WebKit was running on simulator iPhone 5s, which may indicate the device support the latest iOS version. Yet believe in it with difficulty, because the Apple usually does not update obsolete smartphones: iPhone 4s and iPhone 5, the latest supported versions began iOS 9 and iOS 10, respectively.
As noted by 9to5Mac, many of the iOS 12, who visit their website have a resolution of 1136 x 640, which may correspond to the iPhone 5s. However, the same permission is SE iPhone, which with high probability will get an update to iOS 12.
Apple will officially unveil iOS 12 in the framework of the conference WWDC 2018 in June of this year. Initially the new version will be in the format of beta, public release is likely to take place in autumn.