Yeah the Metallica forum has been talking about this for a week or so. Looks like the mixing stage is upon us, and I think Lars said in the month of June they will sit down and pick final songs, titles, album title etc... So it seems like a fall 2016 release is likely.
Kotowboy posts over on the Metallica forum a good bit, he could probably share more info if there is more, but I think that's about it.