The Gates of Ahn'Qiraj will house two massive, unique dungeons -- the Ruins of Ahn'Qiraj, a 20-man raid dungeon, and the Temple of Ahn'Qiraj, a 40-man raid dungeon. As players delve deeper into the mysteries of Ahn'Qiraj, they will discover revelations of the Silithid infestation and their shadowy masters, the Qiraji. Players will have to complete a world event of massive proportions before they can open the Gates of Ahn'Qiraj on their realm. — Patch Notes: Patch 1.9
The raid-lockout system has undergone a significant change. The new system will have all instances reset at a certain server time, regardless of when you were actually saved to the instance. The reset schedule is as follows:
Molten Core: Every 7 Days, resetting during weekly maintenance.
Blackwing Lair: Every 7 Days, resetting during weekly maintenance
Onyxia: Every 5 Days
Zul'Gurub: Every 3 Days
Temple of Ahn'Qiraj (40-man): Every 7 Days, resetting during weekly maintenance
Ruins of Ahn'Qiraj (20-man): Every 3 Days
All resets will occur during off-hours, when the least amount of raids are active.