WebKit testing logs reference iOS 12 running on an iPhone 5s simulator

MacGeneration has spotted discussions in the open source WebKit mailing list that include references to iOS 12. Specifically, a contributor included testing logs of a WebKit nightly build running on an iPhone 5s simulator.

This is strong evidence that the iPhone 5s will receive iOS 12, which was probably to be expected anyway given historical patterns. It’s also just fun to see iOS 12 popping up in places already …

Apple gave the iPhone 4s and iPhone 5 models five years of major updates, cutting them off with iOS 9 and iOS 10 respectively. Therefore, support for iPhone 5s in iOS 12 is not a major revelation although there is never any guarantees. Apple has shown much more irregular patterns of support with the iPad line for example.

It’s also worth pointing out that just because the device can update to iOS 12, it may not be fully-featured. Depending on how well the hardware can handle the new features and functionality, Apple may selectively disable some aspects of iOS 12 on older hardware. With a supposed focus on performance reliability, there may be even more of this than usual.

In our analytics for 9to5Mac traffic, many of the iOS 12 devices are running the 1136×640 resolution that would identify the device as an iPhone 5s, but unfortunately that is also the screen resolution of the iPhone SE and we cannot get more granularity on exact models.

The open-source nature of WebKit has seen various smaller scale features from upcoming iOS features leak out early in the past. This happens because Apple WebKit engineers submit code and tests to the repository without stripping out all the bits that aren’t yet public knowledge. For example, ahead of iPhone 6s, partially-implemented link preview components appeared in open-source WebKit before 3D Touch and Peek and Pop were officially announced.

Along those lines, MacGeneration has also found some private API references which are conditionally available in the iOS 12 and macOS 10.14 releases. Rather amusingly, code review has pointed out that these availability annotations should probably not be using names that reveal the unreleased iOS versions into public codebases: ‘Please use the TBA macros!’.

Apple will officially announce the new operating systems at the WWDC keynote on June 4, about a month and half away. The new WebKit builds will be rolled into the Safari updates as part of iOS 12 and macOS 10.14.

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