We have a data files with an extension ".ppx" for our business app here. Users will typically have multiple versions of the application installed (side by side) for example version 1 and version 2.

The ppx files are xml files and they contain the version of the app they were created from (v1 or v2). Lets say that we have AFileCreatedWithAppv1.ppx and AFileCreatedWithAppv2.ppx opens with version 1 or version 2 of our app respectivly when they both have the same file extension?

It must be doable since that is what Visual Studio does. In fact, they even provide different icons for the same .sln extension to indicate what Visual Studio version it will open with. I learned that Visual Studio is using the Selector or Launcher in between, but then again, how do they change the icons in Windows?

cheers :)