Ruby on Rails 2.3.9 (gem and git tag) 对 2.3.8 进行扩展，使之更接近 Rails 3 和 1.9 的一个桥接版，如果你的应用在 2.3.9 上运行没有任何废弃的警告，那么你的应用就很有希望直接升级到 Rails 3.
该版本废弃的内容有：
- Changes i18n named-interpolation syntax from the deprecated Hello {{name}} to the 1.9-native Hello %{name}.
- Replaces Kernel#returning with Object#tap which is native to Ruby 1.8.7.
- Renames Array#random_element to Array#sample which is native to Ruby 1.9.
- Renames config.load_paths and .load_once_paths to the more accurate config.autoload_paths and .autoload_once_paths.
在这些被声明为废弃的内容中还包含bug修复，详情请看 commit log
Onward to 3.1!
