WordPress: upload new file types media manager

php-wp-add-upload-mime.php

<?php
#add epub,mobi file upload ability
add_filter('upload_mimes', 'addUploadMimes');
function addUploadMimes($mimes) {
  $mimes = array_merge($mimes, array(
      'epub|mobi' => 'application/octet-stream'
  ));
  return $mimes;
}