One new area in act 5, areas in acts 3 and 1 have been expanded with new content.
"Nagelring - Level required for this to drop has been raised from 11 to 40"
Shamblers reported to be most affected by this news.
Oh and you can buy another stash tab, bunch of Crusader skills got replaced, big focus on Thorns, +XP% gain is nerfed post level 70, and a bunch more things:
http://us.battle.net/d3/en/blog/19998542/patch-240-now-live-1-12-2016