Sam Ruby is updating Agile Web Development with Rails, Third Edition for Rails 2.1 in multiple passes. His progress reveals something about the issues that others updating Rails 1 applications to 2.1 will need to address. I mentioned in Are computing books obsolete? that Agile Web Development with Rails, Third Edition covers Rails 2, but is still only available as a beta e-book. I have since gotten a copy of that e-book, and found it useful even in its partially updated form.The new edition is being updated by Sam Ruby. Sam is keeping track of the update status of the book in the Preface. He is, in fact, updating the book for Rails 2.1 in multiple passes. As of June, here’s where he was:Of course, to make complete sense of the above status table you need to look at the book’s table of contents to see what the topics are for each chapter. That can be found here. The subheads correspond to chapters, and Chapter 1 is the Introduction, so The Depot Application is Chapter 5, and Chapter 12, which doesn’t work with Rails 2.1 just yet, is Task G: One Last Wafer-Thin Change. The summary for most Rails applications will probably be “only minor changes were required.” Software Development