Can i install tfs 2013 on server that tfs 2010 is installed? Is it possible to have both versions installed at the same time without any conflict? we want to use tfs 2013 but upgrading 2010 is risky for us, so we decided to just install another version.
You can't install multiple versions of TFS on the same server.
You could install a new TFS 2013 on a separate server so you can try out the 2013 functionality.
Or, you could clone your current 2010 installation and try an upgrade (make sure to run ChangeServerID if on the same network) More details in the Rangers upgrade guide - https://vsarupgradeguide.codeplex.com/