Aion 2's Chapter 1, Lands of Sand and Snow, brought the Brawler class and raised the level cap to 50. Elyos players gained Eltnen and Asmodians gained Morheim, with new progression activities in both areas. The update also introduced Citadel of the Fallen Daeva as an Expedition and Abyssal Horn Den as a Transcendence dungeon.
The less obvious change is how you plan a run
NC removed the old entry tickets for Expedition and Transcendence and moved reward claims to Odyle Energy. Party sizes rose to five for those dungeons and ten for Sanctuary. For a returning player, that changes both scheduling and the meaning of a “free” run: entering and claiming loot are separate decisions.
Chapter 1 also expanded solo challenges and added PvP options including Chaotic Upper Reshanta and Battlefield: Siege. It is a broad systems update, not simply a content drop. Check NC's Chapter 1 notes and the current client before relying on an older build or dungeon route.