Is there a way, perhaps in Visual Studio or from the command line, to find out which version of TFS you are connecting to?
A version can be requested by calling a web service on a TFS server if it is before TFS 2012: http: //tfsserver/VersionControl/v1.0/repository.asmx/GetRepositoryProperties
In TFS 2012 and later, it does not return this information (or, if so, in an encrypted key).
this should give you enough information.