On Thursday June 24th from 3am PDT to 5am PDT (10am GMT to 12am GMT) we will be performing maintenance on our global chat server and patch servers. In-game connectivity will not be affected but you will not be able to log in during this time.
Here is what that means: Anyone in game will be fine and can play to their hearts content. With our patch server being down though, nobody outside the game will be able to connect to our servers to load the game up.
Also we will be doing global chat server maintenance. While the global chat server is down there will be no access to chatting or mail. Unfortunately this also means that I will not be able to actually warn anyone in game, so this is my attempt to get the news out. :)
I will update this thread when there is more information.