If you have a v4.2.3 server simply download the server patch. Turn off your server. Copy files to server(overwriting any old files). And restart server.
If you have an pre 4.2.3 server you can download the couple previous server patches to get you to 4.2.4. Or reinstall the server with a fresh full 4.2.4 install.
We are working on getting a full server install up, should see that soon.