The patch, which landed today, opens up a new Tier 3 raid called Bindings of Blood. In this raid, players are experiencing the binding of the dragons from a first-hand perspective, and in so doing they actually change the "present" history of their personal game.
Trion Worlds told us on the phone that the 20-person raid contains four portals to four instances, each with its own mini-boss, dragon, and unique theme. The instances are on separate lockout timers, and currently two are open with two more scheduled for next month. The bosses are reworked versions of Greenscale, Akylios, Laethys, and Maelforge, and will drop best-in-slot gear and weapons.