I cannot find the above, the nearest I can find is the below:
$lastposts=$DB_site->query_first("SELECT MAX(lastpost) AS lastpost FROM thread WHERE forumid=$forumid AND visible=1 AND open<>10");
if ($lastposts['lastpost']>$lastpost) {
$lastposts=$DB_site->query_first("SELECT lastpost,lastposter FROM thread WHERE lastpost='$lastposts[lastpost]'");
$lastpost=$lastposts['lastpost'];
$lastposter=$lastposts['lastposter'];
}