The probability of monster groups has been adjusted.The probability of Greater Rift maps has been adjusted.Removed: Sewers of Caldeum, and Hidden Aqueducts.Added: Fields of Misery, Desolate Sands and Briarthorn Cemetery.3 maps have been added and 2 maps have been removed from the Greater Rift pool.Fixed a bug that caused Conduit Shrines to deal less damage than intended.Monsters in Echoing Nightmares can no longer be Frozen, Stunned, Rooted or Knocked Back.Increased the possible rank a Whisper of Atonement can drop to 125 based on the Tier completed.The exit timer has been increased to 60 seconds.Updated the Shadow Clone explosion to better reflect the area of effect.Increased the frequency of which monsters spawn.Hellish Machinations now appear, which spawn streams of Exploding Lunatics.Rare monsters now spawn within an Echoing Nightmare.It drops pre-ranked based upon the player's performance in the Echoing Nightmare. The Whisper of Atonement is a Legendary Gem used exclusively for Augmenting Ancient Legendary items.Players receive the following rewards upon completing an Echoing Nightmare: EXP, Legendary Items, Blood Shards, Gems, and a new Legendary Gem, Whisper of Atonement.Players can progress faster by defeating monsters quickly. While within an Echoing Nightmare, the difficulty scales as players progress in the encounter.

Similar to a boss encounter, all players in a multiplayer game must accept a prompt to enter.

Only one player is required to transmute a Petrified Scream to open an Echoing Nightmare in a multiplayer game.Petrified Screams and the Echoing Nightmare can only be accessed with seasonal characters.

Diablo 3 season 21 patch notes