PTR 2.1.0 is up and here are some of the patch notes. Click the link for all of them.

General
- The Black Temple is now available for play and Illidan awaits. Are
you prepared?
- The Consortium and Protectorate need your help! Players with Honored
or higher reputation with the Consortium should seek out Protectorate
Advisor Rahim at the Stormspire in Netherstorm or Commander Ameer at
the Protectorate Watch Post in Netherstorm to get a briefing on the
most recent nefarious activities of the Ethereum.
- Skettis is now available. Players will need a flying mount to reach
this new area.
- Nether Drakes are now in the game and can be gained by continuing the
Netherwing faction and quest line.