In addition to closing a DOS vulnerability (thanks to Jim Meyering), this upstream feature release adds the following enhancements:

• Support for side-by-side diffs
• Support for repo content in "about" view
• Improved integration with gitolite/gitweb
• Support for git notes in commit/log view
• Support for graph in log view (similar to 'git log --graph')
• Improved handling/display of path filters
• Clients can modify diff view parameters
• Support for directory listings in plain view
• Support for remote branches
• Support for range searches in log view (like 'git log master ^stable)
• Support for expansion of environment vars in certain cgitrc options, which can simplify virtual hosting

The release announcement has a more complete changelog:

http://article.gmane.org/gmane.comp.version-control.git/168496