Starting from this EAP, configuration of issue trackers, versioned settings, custom charts, shared resources and third-party report tabs was moved from
<TeamCity Data Directory>/config/projects/<ProjectID>/pluginData/plugin-settings.xml to
<TeamCity Data Directory>/config/projects/<ProjectID>/project-config.xml file. The file now has the
<project-extensions> element which contains all of the above-mentioned project features.
Two-node server configuration
Starting with this EAP TeamCity server can operate in two modes: main TeamCity server (default mode), build messages processor.
If TeamCity server is started in build messages processor mode its functionality is reduced to only one feature - process real time data coming from the running builds.
As you can imagine this mode was added to address needs of really large installations, running several hundreds or even thousand agents on a single server.
Team Foundation Work Items Tracking