https://www.ruby-lang.org/en/news/2016/06/20/ruby-2-4-0-preview1-released/
Ruby 2.4.0-preview1 is the first preview of Ruby 2.4.0. This preview1 is released earlier than usual because it includes so many new features and improvements. Feel free to send feedback since you can still change the features.
下载:
https://cache.ruby-china.org/pub/ruby/2.4/
rvm get head
rvm install 2.4.0-preview1