Thanks to LOTRO’s twitter and facebook account we know that that Update 10 will be loaded to the live servers tomorrow. Patch notes are typically released during the downtime so we’ll see those tomorrow.
— LOTRO (@lotro) March 5, 2013
At this time, I don’t know what the actual downtime will be. I will update this post when we have more information as to when the downtime will happen.
The LOTRO Game Servers will be brought down on Wednesday, March 6th from 7:00 – 10:00 AM Eastern (-5 GMT) to launch the latest game update, Update 10: Against the Shadow, Part 2. Thanks for your patience, and we’ll see you back in the game soon! Patch notes will be available during the downtime.
Source: LOTRO Forums