This is older news now, but it appears that Inferno, the next book in the Horus Heresy series, has been delayed until 2017 judging by the comments made on one of the official forums from Forge World.
Of course, for those following along, the original release date was always going to be something like February 2017. It was simply that the December 2016 White Dwarf rumours and image scans were appearing to suggest it would be in time for the festive season in 2016. And indeed: those White Dwarf sources looked both credible and the dates very real for a release in 2016.
The announcement merely re-sets the release schedule back to what it was originally.
All this said, I really like the "double-whammy" that Games Workshop has pulled for the Thousand Sons appearing in a very short time frame in both 30k and 40k. Plus, we also got the Burning of Prospero on top of that for a triple-whammy. There's little not to like at the moment about Games Workshop and Forge World's release schedule. And I for one can live with a small delay in Inferno!