Moving existing project files to a different location

I read in an article by Paul Filkins <

Maybe it’s buried where you put it!!

multifarious
Projects, packages, segmented SDLXLIFF files, unsegmented SDLXLIFF files, source files, target files, Translation Memories, Termbases, AutoSuggest Dictionaries… are they buried deep in your computer by Studio without you knowing?  Are you really subjected to a message like the one on the left?  Sometimes...
> that it is indeed possible to move existing projects to a different location. He says, "To add them back into the Projects View if you do move them all you have to do is open the SDLPROJ file from the new location and that’s it." However, several of my colleagues say that this doesn't seem to work. When you try to open the file, Studio will tell you, they say, that the project is already present in the project list.

Paul Filkins also says in his article that Studio writes the location of the projects into a file called the projects.xml. I am wondering if this file must perhaps be edited manually for the above procedure to work? And if I move (or copy) existing project folders to a new location, should I also copy the projects.xml file there?

By the way, I have worked in Studio 2011 so far, and I am about to upgrade to Studio 2015. I would like to be able to open my Studio 2011 projects in the new version. Can I move (or copy) them to the desired location before installing and then simply open each project file from the new location in Studio 2015? Will the Studio 2011 projects.xml file also be used by Studio 2015 to locate existing projects created in Studio 2011, or will they be included in a newly created 2015 projects.xml file when opened in Studio 2015?

Thank you in advance for any comments and explanations!