Wordpress 2.3 to Wordpress 2.3.1

When I logged on to my private blog today, dashboard showed up an announcement?that?WordPress?has?latest?update,?WordPress?2.3.1.
Download and install like previous upgrade. Just copy all folders and files, except wp-content and wp-config from Wordpress 2.3.1 to an Old Wordpress, it works like a charm.
You don’t need to runs upgrade.php (wp-admin/upgrade.php). WordPress updates itself.