From
http://weblog.rubyonrails.org/2009/11/30/ruby-on-rails-2-3-5-released
> Rails 2.3.5 was released over the weekend which provides several
> bug-fixes and one security fix. It should be fully compatible with all
> prior 2.3.x releases and can be easily upgraded to with “gem update
> rails”. The most interesting bits can be summarized in three points.
>
> Improved compatibility with Ruby 1.9
>
> There were a few small bugs preventing full compatibility with Ruby
> 1.9. However, we wouldn’t be surprised you were already running Rails
> 2.3.X successfully before these bugs were fixed (they were small).
>
> RailsXss plugin availability
>
> As you may have heard, in Rails 3 we are now automatically escaping
> all string content in erb (where as before you needed to use “h()” to
> escape). If you want to have this functionality today you can install
> Koz’s RailsXxs plugin in Rails 2.3.5.
>
> Fixes for the Nokogiri backend for XmlMini
>
> With Rails 2.3 we were given the ability to switch out the default XML
> parser from REXML to other faster parsers like Nokogiri. There were a
> few issues with using Nokogiri which are now resolved, so if your
> application is parsing lots of xml you may want to switch to this
> faster XML parser.
-igal