public static function getLangs($folder = '')
    {
        $langs = [];

        $iterator = new \DirectoryIterator(ForumEnv::get('FORUM_ROOT').'lang/');
        foreach ($iterator as $child) {
            if (!$child->isDot() && $child->isDir() &&
                file_exists($child->getPathname().DIRECTORY_SEPARATOR.'install.po')) {
                // If the lang pack is well formed, add it to the list
                $langs[] = $child->getFileName();
            }
        }

        natcasesort($langs);
        return $langs;
    }