LOTRO Community Manager Andy “Frelorn” Cataldo posted a notice on the forums about upcoming server downtime:
The LOTRO Game Servers will be brought down on Tuesday, April 12th from 7:00 AM – 11:00 AM Eastern (-5 GMT) for an update to the game. Release Notes will be made available during the downtime. Thanks for your patience, and we’ll see you back in the game soon
This is for the much-anticipated (especially since today’s Developer Diary was posted) Update 18!