Message Filter Extension Impacts

Hello, We are using a Message Filter Extension (ILMessageFilterExtension) to classify SMS/iMessage content (junk vs allow) in our app. After testing on iOS 26.1, we want to confirm whether there are any behavioral, performance, or API-level changes that impact message filtering, such as: Changes in how often the filter extension is invoked Differences in classification accuracy or system overrides New privacy, entitlement, or permission-related restrictions Execution time limits or memory constraints Any changes specific to iMessage vs SMS filtering We did not find any explicit mention of Message Filter Extensions in the iOS 26.1 release notes and would like to confirm whether the existing behavior from previous iOS versions remains unchanged. Has Apple introduced any known or undocumented changes in iOS 26.1 that developers should be aware of when supporting Message Filter Extensions? Sometime I also found unpredictable behaviour on iOS version 18.5 or below, like sometime it works but sometimes starts working.

Thanks in advance for any guidance.

Message Filter Extension Impacts
 
 
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