该版本在修正了一些bug之外，还引入以下新特性：
Active Record
1. touch is a convenient method to update
a record’s timestamp and nothing else. This is extracted from apps
whose models “touch” others when they change, such as a comment
updating the parent.replies_changed_at timestamp after save and
destroy. Timestamping an entire has_many association makes it easy to
build a key for fragment caching that covers changes to the parent
object and any of its children. This pattern is wrapped up as belongs_to :parent, :touch => :replies_changed_at. When the child changes, parent.replies_changed_at is touched. :touch => true is defaults to :touch => :updated_at.
2. :primary_key option for belongs_to for broader support of legacy schemas and those using a separate UUID primary key: belongs_to :employee, :primary_key => 'SSN', :foreign_key => 'EMPID'
JSON
1. decoding backends for the json and yajl libraries.
2. leaner user-facing encoding API
其他方面
1. Add :concat option to asset tag helpers to force concatenation.
2. Restore backwards compatibility for AR::Base#to_xml.
3. Move from BlueCloth to Markdown for the markdown helper.
下载地址：http://rubyforge.org/frs/download.php/60600/rails-2.3.3.zip
详情请看这里。 | 
