Original sentence: The main developers have thrown their weight behind the virtual machine provided by the YARV project, which was merged into the Ruby source tree on 31 December 2006, and released as part of Ruby 1.9.Version 1.9 (the codebase which is the development version of 2.0) was released on 30 January 2008
Edited sentence: The main developers have thrown their weight behind the virtual machine provided by the YARV project, which was merged into the Ruby source tree on December 31, 2006, and released as part of Ruby 1.9.Version 1.9 (the codebase which is the development version of 2.0) was released on January 30, 2008