Apple has seeded the sixth developer beta for iOS 11.4, a mere three days after the fifth betas of Apple's operating systems were distributed for testing ahead of an upcoming public release.
The code is available to developers via over-the-air updates and the Apple Developer Center downloads. Public beta releases typically ship a few days after their developer counterparts.
The sixth iOS 11.4 beta bears build number 15F5079a, up from the 15F5077a from the fifth beta. All previous betas have single build numbers, except the third iOS beta, which was split into two different builds.
Support for Classkit, Apple's framework to help developers to make their educational apps work with Apple's school-based software, is one of the main features of iOS 11.4. Using the upcoming Schoolwork app, teachers can add links that takes students to specific parts of another app for an assignment, with ClassKit enabling the links to function.
Apple has also reintroduced support for Messages in iCloud, a way to synchronize conversations between multiple Apple devices logged into the same Apple ID. Previously announced for inclusion in iOS 11, Messages in iCloud has appeared in betas but has yet to feature in a full public release.
Both the iOS 11.4 and tvOS 11.4 betas include support for AirPlay 2, Apple's upcoming wireless streaming protocol that will replace AirPlay, adding features like multi-room audio. Like Messages in iCloud, Apple previously tested the protocol in the beta for iOS 11.3, but removed the functionality ahead of the final public release.
Sixth betas for macOS 10.13.5, tvOS 11.4, and watchOS 4.3.1 were not released alongside today's iOS beta.