With the upcoming Book 12: The Ashen Wastes, comes a revamp of the entire Angmar region.
MadeOfLions, one of the developers for Lord of the Rings Online, stopped by the official forums, and gave a complete list of the quests that will be 'versioned':
If any of these quests are *currently underway* in your quest log, you should aim to finish them before the update goes live; once it does, these quests will be removed from your quest log and you will need to start the quests over at the bestower. If you have already *finished* these quests, there will be no impact on your quest log.
Click below for the complete list, and head over to the official forums if you have any questions!