Subject and other texts are decoded incorrectly

[mvar]

Current result: test 123 ir lietuviškos raid�s
Expected: test 123 ir lietuviškos raidės

Possible solution (partly tested):

    /**
     * Decodes IMAP encoded string (RFC2047)
     *
     * @param string $string
     *
     * @return string
     */
    public function decodeImapString($string)
    {
        $result = array();
        $parts = imap_mime_header_decode($string);

        foreach ($parts as $part) {
            if ($part->charset == 'default') {
                $result[] = $part->text;
            } else {
                $result[] = mb_convert_encoding($part->text, 'UTF-8', $part->charset);
            }
        }

        return implode($result);
    }

This logic should be applied to header lines (including attachment names)