I encountered the following issue while working with app group preferences in my Safari web extension: "Couldn't read values in CFPrefsPlistSource<0x3034e7f80> (Domain: group.com.protectusexpleo.NewProtectUSFilterApp, User: kCFPreferencesAnyUser, ByHost: Yes, Container: (null), Contents Need Refresh: Yes): Using kCFPreferencesAnyUser with a container is only allowed for System Containers, detaching from cfprefsd." I would appreciate any guidance on resolving this.

Many developers, including myself, are experiencing issues with UserDefaults and App Group containers in Message Filter Extensions on iOS 18. These extensions were working fine in previous versions but no longer function correctly after the update. Could you confirm whether this issue originates from the iOS system itself, or if there are any changes in iOS 18 that affect the functionality of Message Filter Extensions? I will provide a minimal project with steps to reproduce the problem. Please let us know if there are any updates or recommended workarounds. Looking forward to your insights. Best, Mahesh GV

Dear Ziqiao, Thank you for your response. As requested, I have created a minimal project that reproduces the issue. Since external links are not permitted on the forums, please let me know the best way to share the project with you (e.g., email or an alternative upload method). Issue Recap: The Message Filter Extension is not being triggered at all in iOS 18. The handle(_:context:completion:) method inside ILMessageFilterQueryHandling never gets called when an SMS arrives. The same implementation worked fine in iOS 17 and earlier, but it is not functioning after the update to iOS 18. Several other developers are also experiencing this issue and have reported it in Apple Developer forums: Developer 1's Forum Post https://developer.apple.com/forums/thread/764561 Developer 2's Forum Post https://developer.apple.com/forums/thread/766285 Steps to Reproduce: Install the minimal project on a real iOS 18 device (not just a simulator). Enable the Message Filter Extension via Settings → Messages → Unknown & Spam. Check the logs while receiving an SMS. Observe that the filtering method never executes, meaning the extension is not being triggered. Additional Context: I have already updated to macOS Sequoia 15. The issue persists on both real devices and simulators running iOS 18. The extension is correctly set up with App Groups and required entitlements, but it is not receiving any SMS filtering events. Questions: Has there been any change in iOS 18 that affects the behavior of Message Filter Extensions? Are there additional entitlements or configurations required for these extensions in iOS 18? Is there an alternative way to debug or verify whether the system is actually attempting to invoke the extension? I appreciate your time in reviewing this issue and look forward to your insights. Best regards, Mahesh GV

Hi, I've created a minimal project reproducing the issue: Minimal project. Link: https://drive.google.com/file/d/1p5sfXqt-ES6eeTw9V3c4sZGw3GPXWQ0s/view?usp=sharing The Message Filter Extension is not triggered in iOS 18—handle(:context:completion:) never gets called on SMS arrival. It was working fine in iOS 17 but stopped functioning after the update. Could you check the minimal project and help with the following questions? Are there any changes in iOS 18 affecting Message Filter Extensions? Are new entitlements or configurations required? Any known solutions or alternative approaches to achieve this? Looking forward to your insights. Best, Mahesh GV

Hi Ziqiao, Thank you for your response. I have tested the issue on the latest public beta, iOS 18.4 Beta 2, and can confirm that the message filter extension is still not being loaded. To ensure accuracy, I followed the same setup and debugging process as before, but the extension does not appear to be invoked by the system. This confirms that the issue persists despite the fixes mentioned in FB15385442 and FB15266709. As per your suggestion, I have filed a new feedback report with detailed information about my testing environment. You can find the report here: 🔗 Feedback Report - 16730004 link: https://feedbackassistant.apple.com/feedback/16730004 Please let me know if any additional details are required. Best regards, Mahesh GV