From Step 1.1 of this mod remove function get_subcategories_id($cat_id = 0)
{
global $subcat_ids, $cat_parent_cache;
if (!isset($cat_parent_cache[$cat_id]))
{
return false;
}
foreach ($cat_parent_cache[$cat_id] as $key => $val)
{
$subcat_ids[] = $val;
get_subcategories_id($val);
}
return $subcat_ids;
}
v1.7.2 already has this function.