Update: read this story's thrilling (non)conclusion in 2017.
As of August 2016, there are no plans for new editions of any of the books listed on this site's homepage. These books may or may not be updated again, but any such updates would almost certainly not appear before the second half of 2017.
This prognosis includes Programming Python, whose latest 4th edition is still not quite 5 years old; is still fully relevant as an applications foundations tutorial; and presents examples which work well on the most recent Python 3.Xs—including 3.3, 3.4, and 3.5—with only very minor changes. More to the point, this is not a version-specific book; rather than trying to document the transient leading edge which changes from year to year, it teaches fundamental software development tools and techniques that apply to all Python releases.
Though my other two books, Learning Python and Python Pocket Reference, are not version specific either, they were both recently refreshed over the last two to three years to reflect Python's current state. Because these books cover Python 2.X and 3.X language fundamentals that underlie every application domain, they apply to all Python versions and learners. For more on the status of Learning Python, see this note.
While it may be premature to label any of the current editions as final, I hope they will continue to serve Python 2.X and 3.X users for many years to come.
It's also worth noting that the publisher declined to update one of the books (Programming Python) in mid-2015, despite both reader interest and author proposals, and for trivial reasons best elucidated by the publisher itself. Regrettably, there seems to be a broader demotion of books and open source topics afoot at this once-trusted source for both, whose impact on future updates is impossible to predict.
Market demand and the needs of a loyal customer base will hopefully outweigh other agendas in the end. If they do not, though, it's not impossible that these books may eventually appear in a different venue. Although there are currently no formal plans for such a move, I intend to make these resources available to Pythoneers for many years to come—one way or another.
For related notes on the publisher thread, see here, here, and here.