On rested exp issue again.

There have been rumors on this topic since the day is drawing near.

There's green poster saying that rested xp will be rest as you upgrade your account/the launch day, while it will again accumulate afterwards.

http://forums.worldofwarcraft.com/thread.html?topicId=62540657&sid=1
http://forums.worldofwarcraft.com/thread.html?topicId=25171669431&sid=1

and there're people saying that it won't reset and you need to learn how to save rested xp at 80.

http://forums.worldofwarcraft.com/thread.html?topicId=27495544059&sid=2000
http://forums.wow-europe.com/thread.html?topicId=14574718404&sid=1&pageNo=2

So what's the real deal here?