We have a collection in TFS 2012 which contains more than one project. We are considering to migrate to TFS 2013. The TFS servers are already up and running. Is it possible to migrate the data of a specific project in the collection from one TFS server (2012) to the other (2013) or we must migrate the whole collection?
The best way to do it would be to split up the team project in team project collection and then upgrading only the new team project collection. See below for splitting up team project from project collection
http://msdn.microsoft.com/en-us/library/dd936158.aspx
Also, the Tfs To Tfs migration guide will be useful.
http://tfstotfsmigration.codeplex.com/releases/view/37382