Hello , stringValue is used to return" char * and int " values. Below is my code block. livenessMode = [[@"blink,turnLeft,turnRight" stringValue] UTF8String] "stringValue" is running on the IOS 14.7 OS phone, I get the following error on the iOS 15.0 beta phone. ** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSTaggedPointerString stringValue]: unrecognized selector sent to instance 0xb82f333406ee1605' terminating with uncaught exception of type NSException