Yes, there will be a server update today. It will add a few more promotional cards, including a new donation card, so THE SLIME CANNON WILL NOT BE AVAILABLE TOMMOROW.

Many card changes, and some bugs may be implemented.

Also, there will be some changes to gameflow, as well as a change to the way multicolored cards are displayed (which doesn't really affect anything, since the only multicolored card that was in the game before now is Webrunner)

I've made a lot of incremental updates since it started. EG: I think I may have fixed some problems with cards appearing and dissappearing randomly from decks.

The server may be up but not accessable during this time (I have to check some stuff server-side, and whatnot)

On a completely unrelated note, .hack//GIFT is one of the scariest things ever.