New Zone - Zereth Mortis
New Progression System - Cypher of the First Ones
New Raid - Sepulcher of the First Ones
New Mythic+ Season and Score Progression
New Torghast Wing - Jailer's Gauntlet
New Class Bonuses - Return of Progenitor Tier Sets
Equip Double Legendaries - One Covenant, One Normal
Solo Shuffle - New PvP Brawl to test Arena Solo Queue
New Sub-Profession - Proform Synthesis
New pets, mounts, toys, transmog sets, and secrets...
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Also the currency matches certain region.