From Press Release:
Path of Exile: Sentinel, the latest expansion to the renowned free-to-play action RPG, is now available on PC and macOS, and will be coming to PlayStation 4 and Xbox One on May 18.
Path of Exile: Sentinel will feature the Sentinel Challenge League, 20 atlas keystone passives, seven uber boss fights, new pinnacle unique items, revamped monster modifiers, game controller support, new quality of life features, a revamped challenge system and much more!
Grinding Gear Games has broken down the content in the expansion through several updates and pieces of content over the past week: