As far as I can remember it was part of the november patch, along with Lost Shores. Should be on the patch notes there.
EDIT: Yep it was under the 'Items' Section:
The amount of loot that drops for downscaled players has been increased. You should now be able to receive level-equivalent loot until you are fighting at a downscaled level that is less than 2/3 of your actual level. You should also receive loot a greater percentage of the time as well as receiving a greater percentage of experience, gold, and karma. For level 80 characters, this means level 55+ areas will be able to drop level 80 gear and give about 75% or so of the other rewards. Previously, these areas would give level 77 gear at best and closer to 60% or so of your rewards.
Edited by Dawn Quickblade, 06 December 2012 - 04:09 AM.
Making quote easier to read.