Just remembered
Over a month ago, Allen & Urwin sent out an email to their subscribers of the Keys to the Kingdom newsletter that Garth Nix had sent in the first draft of the last book, Lord Sunday. The publishers have basically stated in that same email that we can expect the book early next year. So, my prediction of him bring it out the end of this year was a bit off, but I don’t care any more. I’m looking forward to Five Greatest Warriors.