The version 2.3 is the latest version of the GN4. You can download the version 2.3 from the 2.3 section on the technical Web site.
This chapter lists the new and enhanced features, performance improvements and bug fixes in the version 2.3.
See also
Version 2.3 presentation (Powerpoint 2013, 170Mb - sign in required)
Use the Table of Contents to find information. See also Using table of contents in help.