Players are reporting that the recolored white/blue Night Elf Heritage Armor is now available in-game, as well as the New Beginnings questline that wraps up the Amirdrassil story.
Based on reports from Reddit, Wowhead comments, and Twitter, late last night, this questline was accessible to players who defeated Fyrakk in the Amirdrassil raid. Outside of the raid instance, Tyrande will offer the A Blossom Witnessed quest to start the final New Beginnings chapter.
However, not all players who have defeated Fyrakk can see this quest, so perhaps it is rolling out slowly, only available to Night Elves for now, or has some other hidden criteria. We will update as we know more, and stay tuned to our walkthrough of the questline!
Along with this questline, Night Elf players can finally acquire the Ensemble: Raiment of Amirdrassil, a blue and white recolor of their Heritage Armor.