Apple is finishing off the testing of some of its operating systems, and has issued the "GM" versions of of iOS 15, iPadOS 15, watchOS 8, and tvOS 15 for testing.
The latest beta builds, and GM builds, can be downloaded via the Apple Developer Center for developers enrolled in the program, or via an over-the-air update on hardware running the beta software. Public betas usually arrive within a few days of the developer versions, via the Apple Beta Software Program website.
A GM build signifies that Apple is very close to the final version of the release of the operating systems, one that would ship as a full release and not as a beta. Typically, the release occurs to coincide with the launch of major products, which this year includes the iPhone 13.
The ninth beta round consisted of one release for tvOS 15 on September 7. As other operating systems didn't see a release, this made tvOS one generation ahead of the remainder.
iOS 15 introduces Focus modes, as well as Live Text OCR, a digital ID to Wallet, enhancements to FaceTime and Messages, and major improvements to Weather and Maps. From the fourth beta, the Camera app was found to have the ability to remove unwanted lens flares from images.
For iPadOS 15, Apple refined the multitasking features, as well as introduced home screen widget support, a system-wide Quick Note feature, and the Translate app. Arguably the most important change is enabling app development and App Store submissions in Swift Playgrounds.
Users of watchOS 8 will benefit from the addition of Tai Chi and Pilates workouts to the Fitness app, the Sleep app will gain respiratory rate data, the Photos app has new mosaic layouts and memories, and Messages will gain Digital Crown cursor control and GIF search.
AppleInsider, and Apple itself, strongly advise users avoid using beta or test release software on "mission-critical" or primary hardware, due to the small chance of data loss or other issues. Instead, testers should install betas onto secondary or non-essential devices, and to make sure there are sufficient backups of important data before updating.