In early April a new area was announced on the ESO site (here) called Craglorn; a new area/zone in Tamriel, just east of the Daggerfall Covenant territories and intended for groups. The Craglorn site is here. Craglorn will be like other zones with quests and towns however it will be designed with 4 person groups in mind and features designed for 12 person groups as well. This new zone is dubbed Adventure Zone, with respect to its group focus. It will be available to those Veteran Rank 1 and above; with new Veteran Ranks 11 and 12 added with its release. A Q & A was posted on the ESO site here.
Tamriel Journal has a good article on the new zone here (spoilers).
Game Breaker has an article with what it claims are the patch notes for Craglorn’s release; you can see it here. A good article on the ESO site (here) covers the 12 person trials. The story of Craglorn steams from the disappearance of the constellations and their absences impact on Craglorn. The actual release date remains to be clear but the content itself sounds and looks great.