I've looked through a number of previously accepted answers, but none seem to work/apply to the latest versions of WordPress.

I'm trying to allow .rfa file types to be uploaded to the media library.

This is what I've found from a previous answer;

function additional_mime_types($mime_types) {
  $mime_types['rfa'] = 'application/octet-stream';
  return $mime_types;
add_filter('upload_mimes', 'additional_mime_types', 1, 1);

How can I allow .rfa file types to be uploaded to the media library?

  • Sorry, I don't see a question here. What are you actually asking? – kraftner Jan 11 '18 at 17:46
  • to work, this filter must be hooked with priority 10 or above. – mmm Jan 11 '18 at 18:49

I had the same issue, it looks like WordPress isn't able to determine the correct MIME type for RFA files, so it defaults to:


Changing the MIME type to this fixed it for me. So it would be:

add_filter( 'upload_mimes', function ( $mime_types ) {
    $mime_types['rfa'] = 'application/CDFV2-unknown';
    return $mime_types;
} );

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