With only weeks remaining before the official release of iOS 13, Apple surprised developers today with a beta version of iOS 13.1. Today’s update appears to contain plenty of bug fixes, but also includes audio sharing support, enabling a single device to output music simultaneously to two pairs of AirPods.

The developer beta is particularly noteworthy because a number of nontrivial bugs have persisted throughout the iOS and iPadOS 13 beta cycle, some of which may well ship with the final OS release next month. Some of the bugs affect core first-party apps such as Mail and Safari, while others may limit the functionality of third-party apps.

Traditionally, Apple triages beta releases to eliminate their biggest issues before general release, in some cases temporarily delaying nonessential features that are particularly challenging to implement. Audio sharing support, which calls for synchronized Bluetooth connections to multiple devices, appears to have met the nonessential threshold this year, but will in iOS 13.1 enable iPhone 8 or later, iPad (5th generation) or later, and iPod touch (7th generation) devices to connect simultaneously to two pairs of AirPods and Beats PowerBeats Pro headphones.

Another new iOS 13.1 feature, support for encoding HEVC videos with alpha channels, enables videos to be recorded with backgrounds that can be made transparent or invisible, for compositing or editing purposes. It may have been added to facilitate realtime editing of video backgrounds — a specialty of Apple-acquired developer Spektral — or to ease green screen-style compositing of live video with still photo or pre-rendered backgrounds, like Apple’s iMovie and Clips applications.

Apple’s iOS 13.1 developer beta is available now through the software update mechanisms on iPhones. It’s unclear whether it will also become available as a public beta prior to the general release of iOS 13, which is expected to take place shortly after an annual Apple media event next month.

Updated at 10:54 a.m. Pacific: Apple has also released a developer version of iPadOS 13.1, specifically for its tablet devices, which can similarly be accessed through the over-the-air software update mechanisms on iPads. Like the iOS 13.1 release, it’s a roughly 400MB patch to existing iPadOS 13.0 installations.