Following last week’s release of the final public version of iOS 11.3, Apple today released the first developer beta of iOS 11.4 for iPhones, iPads, and iPod touches. A public version of 11.4 beta will follow in the near future, but may or may not be the same as the first developer release.

iOS 11.4 includes support for Apple’s new ClassKit API, enabling development of more robust educational apps and deep links within apps. Additionally,┬áiOS 11.4 appears to re-introduce AirPlay 2, including the left and right HomePod speaker pairing option that previously appeared in iOS 11.3 betas, only to be removed before the final release. iCloud synchronization of Messages has reappeared after similarly being similarly pulled from 11.3. Regardless, we urge caution if you’re considering updating to this beta release, as we’ve already noticed major lags in the OS, including on features such as HomePod control.

The developer release of iOS 11.4 includes support for all iPhones from the iPhone 5s through iPhone X, all iPads from the iPad Air and iPad mini 2 through the iPad Pro 10.5-inch, and the sixth-generation iPod touch. It is approximately 300MB in size as a delta update from the last beta release of iOS 11.3.

Apple also released the developer beta of tvOS 11.4 for the fourth-generation Apple TV and Apple TV 4K, as well as the watchOS 4.3.1 developer beta for Apple Watch. The company generally does not release public betas for the Apple Watch.