[Ted S]

Should be simple enough to hack in...

Pop open includes/functions_databuild.php

Find

$bdays = $vbulletin->db->query_read_slave("
  SELECT username, userid, birthday, showbirthday
  FROM " . TABLE_PREFIX . "user
  WHERE (birthday LIKE '$todayneggmt-%' OR birthday LIKE '$todayposgmt-%')
  AND usergroupid IN ($usergroupids)
  AND showbirthday IN (2, 3)
  $activitycut
 ");

And replace it with

$bdays = $vbulletin->db->query_read_slave("
  SELECT username, userid, birthday, showbirthday
  FROM " . TABLE_PREFIX . "user
  WHERE (birthday LIKE '$todayneggmt-%' OR birthday LIKE '$todayposgmt-%')
  AND usergroupid IN ($usergroupids)
  AND showbirthday IN (2, 3)
  AND posts > 250
  $activitycut
 ");

You'll either have to wait for the birthday list to recompile or you can manually update it. You should be able to do by running this script:

<?php
error_reporting(E_ALL & ~E_NOTICE);
require_once('./global.php');
require_once(DIR . '/includes/functions_databuild.php');
$birthdaystore = build_birthdays();
DEVDEBUG('Updated Birthdays');
echo "Done";
?>

Just save it as birthday.php in your main directory and run.

Note: This is untested so please test it before going live.