The new build for the stable 8.0.x branch is available for download.
It includes fixes for the found critical issues and features support for recent updates: NUnit 2.6.3, MSBuild and Visual Studio project runners for VS 2013.
Please note that TeamCity Add-in and .NET inspections/duplicates are note yet updated with VS 2013 support. Please vote/watch corresponding issues which are likely to get updates in the following weeks.
This version still uses the same database format as all the rest of TeamCity 8.0.x, so you can downgrade if something goes wrong after the upgrade.