Back in xcart 3.5, the admin contained an option to reverse the default display order of products. Now in xcart 4.+ we have options to sort products by SKU, Name, and Price, but have lost the ability to reverse the default listing direction (unless I'm mistaken). To do this in 4.+, you have to make one small change under the hood.
In /products.php look for
Code:
if(!isset($sort_direction))
$sort_direction = 0;
and change this to
Code:
if(!isset($sort_direction))
$sort_direction = 1;
Note that this will only reverse the default display order on product listings on category pages - not in search results or in the admin.
This was done in xcart 4.0.13