Crowley and Daemonomania: Tetralogy or Trilogy?

Is it certain there is to be a fourth book in the series? I am thinking of Chapter 16 in Daemonomia: "Here he had put down his plan to arrange his book according to the twelve house of the Zodiac, four Books, three Parts to a Book, Spring Summer Autumn Winter, Air Fire Water Earth. "Astonishing the crust he was then capable of, the nerve." This is of course Pierce thinking about the book he has not written, but it might also be Crowley abjuring his original plan in a Prospero-like fashion. Both the inner Bruno-Dee and the outer Pierce-Rose narrative seem to be fully completed at the end of this third volume...and collapsing a (pagan) four-part structure into a (Christian) three-part structure would be thematically relevant. Or is Crowley planning to emulate Lawrence Durrell's Alexandria Quartet with a fourth volume quite unlike the previous three?

Alice almost certainly has more detailed information on this than I do, but at this year's ICFA, Crowley assured people that the fourth book was coming, relatively soon (he strongly implied 2002). It will be shorter than the first three, and set in 2002 rather than the 1970s. So, yes, it will be unlike the first three in that way.