“We are adjusting the schedule for the opening of Tiers 4 and 5 of the new raid The Fall of Khazad-dûm by one week to allow players more time to prepare for the opening of these higher tiers. Tier 4 is now expected to open at Noon Eastern (-4 GMT) on June 24th, with Tier 5 opening at Noon Eastern (-4 GMT) on July 8th. The Leading the Charge and Original Challenger deeds will also be available for an additional week, and are now available through August 18th.”
Update 30 rolled out to subbers on Tuesday; in addition to the raid, it includes a new region and story pack.
Source: Official site