Update 16 will be released on Monday, May 4, 2015. This update contains quite a bit of new material. Some of the things it contains: 3 new areas in Gondor; Legacy Imbuement; 3 new Instances; new awards....and more. When released, Patch Notes link will be posted here.
UPDATE (5/4/15): Find the Patch Notes here.
Also look for posts on Imbuement, Dev Diaries and more in this forum.