I have a need to sync up with a legacy source control which is using VSS.
I cannot find any documentation on how to get/enable VSS in Visual Studio 2015 Professional (from MSDN license).
I have looked at the dropdown in the Source Control menu, under Tools -> Options, and the only plugins that exist there are Microsoft Git Provider, Microsoft Team Foundation Server, and None.
FYI - I found this: http://www.dynamsoft.com/blog/version-control-how-to/how-to-connect-visual-studio-2013-to-visual-sourcesafe/
Seems this is a viable solution (although it is only a 30 day trial). Will mark as answer unless a free way is provided.
Install the SourceSafe patch below to enable Visual Studio to display SourceSafe in its Tools|Source Control Plug-in list https://www.microsoft.com/en-us/download/details.aspx?id=291
来源：https://stackoverflow.com/questions/34291555/visual-studio-2015-professional-and-visual-sourcesafe-vss