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 Monday, December 7th from 8:00 AM – 11:00 AM Eastern (-4 GMT) for an update to the game. Thanks for your patience, and we’ll see you back in the game soon! Patch notes will be available during the downtime.
This will be update 17.1.