The Forgeworld books have run their course? well they apparently have and new books are being worked on to replace the rule sets you have. Here is the official announcement.
Since it would be high unlikely to get new Forgeworld books and then a new edition to 40k 6-8 months later, it seems likely that this is a solid hint that the rumors of a new edition coming for 40k mid year are likely. Interesting.
via the Warhammer Community