Well, Age of Sigmar is changing a bit more terminology. You can do that sort of thing when the universe explodes and you get to make a new one. So the Lizardmen are no more. However, in their place are the Seraphon. They even use the same models and everything. Though some of the names there, too, have been changed (to protect the innocent?). Anyway, the new book for the army is available to pre-order from the GW webshop.
As usual, there's a Limited Edition version if you feel so inclined. The regular book is 144 pages long and has the whole backstory of the Seraphon, Warscrolls for all the units, painting guides, and six battalion lists for how you can customize your forces. There's also all the info about how to play Age of Sigmar. Hey, it's just a couple pages, so why not have it in there?