As I did after the last major TFS release, the TFS Administration Tool has been updated to depend upon the TFS 2013 Object Model. You no-longer need Team Explorer 2012 installed to use the tool. It can be installed on machines running either the stand-alone object model (https://aka.ms/TFSOM2013), TFS 2013 or Visual Studio 2013.
This release supports SharePoint groups/roles, thanks to a community contribution. There are no other major functional changed between the release and the previous (2.2) release.
Currently, the MSI in the downloaded ZIP file is flagged by Windows SmartScreen as “unsafe” – based upon the experience of the last release, in about a week, it will build enough “reputation” to be considered safe.
If you find a bug, the best way to get it fixed is to upload a patch. You can also open an issue and include either the contents of the "Output" window or the contents of the log file saved in the "Logs" folder so that we can easily reproduce and investigate the problem.