As of fall 2020, there are no plans for new editions of any of my O'Reilly Python books, and I don't expect this to change. This is partly because Python now morphs too rapidly for comprehensive language texts to keep up, and partly because my texts' publisher now soft-pedals books for the sake of online-learning subscriptions, which regrettably opens a Pandora's box of tracking, marketing, and sales of personal information and customer access.
Reasons aside, it's nearly safe at this point to assume that the books won't be updated again (and the "nearly" is there only because life can be an awfully dynamic enterprise). There's more on this story in the 2017 status update; the ongoing subplot of Python's thrashing and convolution; and the latest coverage of the publisher's ethics endgame.
Most of the earlier words below also still apply—especially their recommendation to learn the fundamentals presented in the books first, and consult Python's What's New documents later for the constantly morphing bleeding edge. Python will always change, but its core concepts and tools covered by the books will be just as relevant decades hence as they were decades ago.
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, and are a recommended first step for Python newcomers seeking a deep-learning experience. For more on the status of Learning Python, see this 2016 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.