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Rails 2.1 was the latest and greatest when this book was written, but Rails continues to evolve. An easy way to keep an eye on Rails is to visit Riding Rails, the website for core Rails development announcements, at http://weblog.rubyonrails.com/. Their “This Week in Rails” series catalogs new Rails articles and software releases, while “Living on the Edge” explores what’s coming (and sometimes going) in Edge Rails, the cutting-edge version of Rails that occasionally turns into the next release.
If you’d like to talk rather than read, the #rubyonrails IRC channel on http://irc.freenode.net is usually busy. You can find more information and logs of past conversations at http://wiki.rubyonrails.org/rails/pages/IRC. In email, the rubyonrails-talk list on http://googlegroups.com churns through 100 or more messages a day, at all levels of difficulty.