"What are configuration categories?"

http://www.wowdev.wiki/index.php ... gories.dbc

Configuration categories, defined in the Cfg_Categories.dbc file, are more or less different timezones or 'types' for your server. On Retail, there are separate realm lists for English, German, Spanish, Russian etc clients.

This guide will show you how to use configuration categories to create custom timezones for your server.
A very good use for configuration categories is ensuring that players can only access your server with a certain MPQ patch.

First of all, extract Cfg_Categories.dbc from your client data and open it in your favourite DBC editor.
I am using Taliis Editor.

Simply create a new row and refer to the Wiki when you are entering your information.

The next step involves actually putting your custom timezone to use in your server.
I am using ArcEmu for this - I have no idea how other cores configure their server's data.
Nevertheless, go into your where your server's config files area and open realm.conf.
Scroll down until you see 'RealmType'. Change this to the ID of your new entry in the categories file.
Save your changes and start up your server, then open up Wow and log in.
(You may want to create two different servers with different timezones to test out the changes.)

If you don't have the custom patch in your data folder, you will not be able to access the server.
This process will stop new players from seeing broken content by simply forgetting to download a patch.

Just to inform everyone - after changing my email address and other details I decided it would be necessary to have a new account here on Modcraft. As my signature states; I was previously called Fellfoxen on these forums. If you have any questions, do not PM the 'fellfoxen2' account. Thanks.