I'm developing a TTS Audio Unit Extension that needs to write trace/log files to a shared App Group container. While the main app can successfully create and write files to the container, the extension gets sandbox denied errors despite having proper App Group entitlements configured. Setup: Main App (Flutter) and TTS Audio Unit Extension share the same App Group App Group is properly configured in developer portal and entitlements Main app successfully creates and uses files in the container Container structure shows existing directories (config/, dictionary/) with populated files Both targets have App Group capability enabled and entitlements set Current behavior: Extension can access/read the App Group container Extension can see existing directories and files All write attempts are blocked with "sandbox deny(1) file-write-create" errors Code example: const char* createSharedGroupPathWithComponent(const char* groupId, const char* component) { NSString* groupIdStr = [NSString stringWithUTF8String:groupId]; NSString* componentStr = [NSString stringWithUTF8String:component]; NSURL* url = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:groupIdStr]; NSURL* fullPath = [url URLByAppendingPathComponent:componentStr]; NSError *error = nil; if (![[NSFileManager defaultManager] createDirectoryAtPath:fullPath.path withIntermediateDirectories:YES attributes:nil error:&error]) { NSLog(@"Unable to create directory %@", error.localizedDescription); } return [[fullPath path] UTF8String]; } Error output: Sandbox: simaromur-extension(996) deny(1) file-write-create /private/var/mobile/Containers/Shared/AppGroup/36CAFE9C-BD82-43DD-A962-2B4424E60043/trace Key questions: Are there additional entitlements required for TTS Audio Unit Extensions to write to App Group containers? Is this a known limitation of TTS Audio Unit Extensions? What is the recommended way to handle logging/tracing in TTS Audio Unit Extensions? If writing to App Group containers is not supported, what alternatives are available? Current entitlements: <dict> <key>com.apple.security.application-groups</key> <array> <string>group.com.<company>.<appname></string> </array> </dict>

We've identified a regression in iOS 26.0 and 26.1 Beta 4 where AVSpeechSynthesisVoice(language:) no longer respects user-selected voices from Accessibility settings. Issue: When users select a specific voice in Settings → Accessibility → Spoken Content → Voices, calling AVSpeechSynthesisVoice(language:) returns the system default voice instead of the user's selection. This worked correctly in iOS 18.6.2. Particularly affects: Third-party speech synthesis voices (CereProc, Grammatek, etc.) Apps relying on automatic voice selection based on user preferences Example: // User selected CereProc Heather for en-GB in Accessibility settings let voice = AVSpeechSynthesisVoice(language: "en-GB") print(voice?.name) // iOS 18.6.2: "HEATHER", iOS 26: "Daniel" (system default) Interesting observation: The new Accessibility Reader feature in iOS 26 correctly uses the user-selected voice, but Tap to Speak and the API both ignore the setting. Tested methods: AVSpeechSynthesisVoice(language:) AVSpeechUtterance auto-selection Reflection for new APIs All return the system default voice, not the user's preference. Filed: FB[20271264] Has anyone else encountered this? Any known workarounds to programmatically access the user's preferred voice selection?