Apple is releasing a new beta firmware build for multiple AirPods models as part of testing for features planned with iOS 27 and related releases. The update is the fourth beta firmware version Apple is testing for AirPods Pro 2, AirPods Pro 3, AirPods 4, and AirPods Max 2. The firmware build number is 9A5336b, replacing a prior beta build identified by AppleInsider as 9A5314b. MacRumors reports that the firmware adds support for changes associated with iOS 27, including a new AirPods interface, a slider for Adaptive mode, and support for custom EQ. It also describes compatibility with an updated Siri AI feature tied to iOS 27. AppleInsider characterizes the release as a continuation of developer testing of inbound iOS 27-related AirPods capabilities. The firmware is distributed as a beta option accessible in AirPods settings on iPhone, iPad, or Mac when paired with devices running iOS 26, iPadOS 26, or macOS 26 or later. Updates are installed by connecting the AirPods to an Apple device and charging them, and there is no standalone software update option for the AirPods beyond the beta toggle and charging process.