I want iPhone users to allow upload a recorder audio file. At first I got error about m4a extension not allowed. Then I addedd m4a as file type, and now the error is "Sorry, unable to check extension of this file type audio/x-m4a."

I am using LimeSurvey Community Edition Versio 6.16.13+260316. My config.php does not contain magic_database -setting. I think that PHP is quite normal too, no changes on mime magic. OTOH when testing with file-command I get "ISO Media, Apple iTunes ALAC/AAC-LC (.M4A) Audio" from the .m4a file as I guess it should be.