Modify mime type in wordpress

functions.php

<?php
/**
 * Modify wordpress mime types
 * @param  array $existing_mimes current mimes
 */
function modify_mime_type($existing_mimes){
	return array_merge($existing_mimes, array(
		'7z' => 'application/x-7z-compressed',
		'rar' => 'package/rar',
		'tar' => 'package/x-tar',
		'tgz' => 'application/x-tar-gz',
		'apk' => 'application/vnd.android.package-archive',
		'pkpass' => 'application/vnd.apple.pkpass',
		'zip' => 'package/zip',
		'gz|gzip' => 'package/x-gzip')
	);

	return $existing_mimes;
}

// Add new mime type
add_filter( 'upload_mimes', 'modify_mime_type' );