[Colin F]

If you just want that code to work with 3.5, use this:

$newestthreadidq = $db->query_read("
                                SELECT threadid
                                FROM thread
                                ORDER BY threadid DESC
                                LIMIT 1
                                ");
$newestthreadid = $db->fetch_array($newestthreadidq);
$newestpostidq = $db->query_read("
                                SELECT postid
                                FROM post
                                ORDER BY postid DESC
                                LIMIT 1
                            ");
$newestpostid = $db->fetch_array($newestpostidq);
$formattedthreadid = number_format($newestthreadid[threadid]);
$formattedpostid = number_format($newestpostid[postid]);