Address Sanitizer and Thread Sanitizer might hang on macOS 26.4 and visionOS 26.4

*VisionOS 26.4 RC Release Notes

Overview
The visionOS 26.4 SDK provides support for developing apps for Apple Vision Pro devices running visionOS 26.4 RC. The SDK comes bundled with Xcode 26.4, available from the Mac App Store. For information on the compatibility requirements for Xcode 26.4, see Xcode 26.4 Release Notes.

Address Sanitizer
Known Issues

• Address Sanitizer and Thread Sanitizer might hang on macOS 26.4, iOS 26.4, tvOS 26.4, watchOS 26.4, and visionOS 26.4 when building with Xcode 26.3 or older. (171762808)

Workaround: Use Xcode 26.4 when testing applications with Address Sanitizer or Thread Sanitizer.

Background Assets
New Features

• You can now check the status of an asset pack while offline by calling localStatus(ofAssetPackWithID:) or assetPackIsAvailableLocally(withID:) on the shared asset pack manager. The former method returns all available status information. The latter returns only a Boolean value but can be called synchronously. Not all status information is available offline. (164498466)
• You can make the latest version of an asset pack available locally by calling ensureLocalAvailability(of:requireLatestVersion:) on the shared asset pack manager and passing true to the shouldUpdate parameter. (166237389)

Resolved Issues

• Fixed: Apps might crash when downloading asset packs. (169648111)

Foveated Streaming
New Features

• visionOS 26.4 supports NVIDIA CloudXR with foveated streaming, enabling apps to display high-resolution, low-latency immersive content on Apple Vision Pro. To implement this new feature, refer to the Apple Developer documentation for FoveatedStreaming. (170184382)

Resolved Issues

• Fixed: The current remote streaming API public static func remote (serverName: String) does not include the signaling headers which is used for Vision Pro connection with the server. The signaling headers can be used for authentication and for manipulating the remote scene. (170085006)

Known Issues
If the user takes off Apple Vision Pro while using the ‘FoveatedStreaming’ feature to stream CloudXR-enabled content, the steam will not pause as expected and the battery will drain. (171672303)

Workaround: Setup passcode in Vision Pro to avoid this issue

Managed App Distribution
Known Issues

• ManagedAppView might render blank when multiple apps are displayed simultaneously in Managed App Distribution. (171016274)
  Workaround: Display a single ManagedAppView in Managed App Distribution.

Networking
Resolved Issues

• Fixed: Multiple processes leak CFRunLoopSource objects when Automatic proxy configuration (PAC) or Auto proxy discovery are configured.

For clients of the CFNetworkExecuteProxyAutoConfigurationURL and CFNetworkExecuteProxyAutoConfigurationScript API, please check to make sure your process is not working around the leak by overreleasing the CFRunLoopSourceRef returned by those functions or the CFArrayRef and CFErrorRef passed to the completion. (166839810) (FB21376045)

StoreKit
New Features

• New fields revocationType and revocationPercentage have been added to Transaction. (148858551)

Resolved Issues

• Fixed: Purchase Intents might not be emitted from the intents sequence when the app is launched from the background. (168958783) (FB21767675)

SwiftUI
Resolved Issues

• Fixed: SwiftUI does not surface the latest .userActivity as the current user activity. (163136831)

Known Issues

• Multiple implicit SwiftUI animations (triggered by RealityViewContent.animate or Entity.animate) that modify a RealityKit component’s properties, are combined only when the implicit animations target the same set of component properties.

For example, if you initiate an implicit animation on Transform.scale and then initiate an implicit animation on Transform.scale and Transform.translation then the animations affecting the scale property will be independent of each other, and will not combine. In this case, the most recently initiated animation will overwrite the scale property. (169723142)

Workaround: Ensure the same component properties are animated by subsequent implicit animations when possible.