http://www.kpsforum.com/den-general-...read-here.html
Also, usually these forums has a note, also the loader, IF the server has upgraded to next patch.
There for, DO NOT update the game if you still want to play on The Den.
Of course, you can make a copy of 2.2.3 before you update to 2.3.0, this way you still can play on Retail + The Den but it takes another 8GB from your free space.

- Saz