I have few SSIS
packages which is developed using VS2013
(.NET 4.5 Framework
) in one solution.
And few packages which are developed using
Additionally, TFS 2013 support TFS 2012 build controller/agent, so you can install TFS 2012 build controller/agent(on another new machine which installed VS 2012 Update 5) to connect your TFS 2013 Server collection, then use default TFS 2012 build template in build definition and specify TFS 2012 build controller in it. This TFS 2012 build server will be the dedicated build server to build VS 2012 solutions.