Thunderbird "Tags" in IMAP / PHP

Thunderbird allows to flag messages with predefined (or own) Tags, e.g. "To Do", "Later". (Press "1" while reading a msg to see.)

These tags are replicated to the IMAP server (I verified that by using two TB clients: I saw the same tags on both clients).

How can I access the tag information in PHP using the standard IMAP class (e.g.: msg has set tag "To Do")?

I found an old reference http://www.wynia.org/wordpress/2007/02/alternate-imap-solution-for-php-pear-net_imap to net_imap http://pear.php.net/package/Net_IMAP, claiming the "standard" IMAP class cannot do this - but the Net_IMAP package doesn't se开发者_如何学Cem to be updated for quite some time, so I am skeptical to adopt it...

Not a perfect answer how to do that via PHP but good enough where to start:

• Server-Side Message Labels
• idea how to handle via IMAP

$messages = imap_search($imap_stream, 'To Do');

PHP.net: imap_search