There has been a book being promoted for pre-order on multiple bookstore sites called "Aperture 4, Unleashing Your Workflow", by John Lewell. Originally set for release in July, many sites later stated the book would be delayed until October. Well... here we are in October, and we are still on Aperture 3.3. With those parameters, I believe there is a strong possibility that Apple will announce their upgrade to version 4 alongside their hardware updates at their big event on the 23rd. Makes sense. This is especially true considering that Lightroom 4 has taken a big chunk of Aperture 3 users away due to better noise reduction, and lens corrections. Apple can't want to fall any further behind, and this carries through to a loss of revenue for their photo book printing business as well. This is all speculation, but this IS a rumor site, and I think there are good indications that the update could be forthcoming shortly...as in next week!