It is so they can prepare the servers for Publish 81 if I am correct.
All shards are being brought down, at once, for some odd reason.
A day of UO lost for the none US players I guess.
Posted by Tim Chappell | 2013 Apr 09 20:33 -0400 GMT
We are taking down all shards tomorrow starting at 11:00 a.m. EDT (17:00 CEST). During this time we will be patching new clients in preparation for Publish 81 for all the shards. In addition, published 81 will be published to Origin and Izumo.
At the moment we anticipate the shards to be back online by 3:00 p.m. EDT (21:00 CEST).