Two weeks following the release of first beta, Apple has released second iOS 11.4 beta for iPhone, iPad and iPod touch, and it is now available for download. The developer specific update can now be downloaded over-the-air and through the developer center.
After the major iOS 11.3 update, the iOS 11.4 software update is a minor update that brings previously announced features like Messages in iCloud and AirPlay 2. Talking specifically about beta 2 in this release Apple has removed the HomePod Stereo Pairing feature and added the new wallpaper featured on marketing materials for (PRODUCT)RED iPhone 8. The wallpaper however has only been added for iPhone 8 and iPhone 8 Plus, and not for iPhone X. You can download the said wallpaper here.
In addition to iOS 11.4 beta 2, Apple has also released watchOS 4.3.1 beta 2 and tvOS 11.4 beta 2 for developers. Both of these are available for download through the developer center on their respective devices.