Apple has released the second beta versions of iOS 11, macOS 10.13 High Sierra, tvOS 11, and watchOS 4. Each update is available now for users participating in the developer beta testing programs.
The easiest way to get the beta 2 updates of iOS 11, macOS High Sierra, tvOS 11, and watchOS 4 are through the over-the-air software update mechanisms. If you’re a developer and have not yet enrolled an eligible device with a beta profile, you can do so at the Apple Developer Center website.
iOS 11 developer beta 2 is available now through the software update mechanism within the Settings app of iOS.
macOS High Sierra 10.13 developer beta 2 is available as an update through the Mac App Store Updates tab.
watchOS 4 beta 2 and tvOS 11 beta 2 are also available now from their respective software update mechanisms.
Beta operating systems are notoriously unreliable and unstable, and thus not fit for regular users. Always back up a device before installing beta system software.
Technically the developer preview builds of iOS 11 beta can be installed by anyone without a developer account or UDID registration, but it is not recommended to do so. These early beta builds are truly only intended for developers only.
Non developers who are interested in running beta system software to experiment with the more fascinating new features in iOS 11 and the features in macOS High Sierra 10.13 will have an opportunity to do so later in the month when the Public Beta testing program opens for macOS High Sierra and for iOS 11.
If you have installed iOS 11 beta and decide you want to downgrade from iOS 11 beta back to iOS 10, you can do that with these instructions
The final versions of iOS 11 will be released in the fall and macOS High Sierra has a similar release date trajectory.