I have created a .msix version of my installer (using MakeAppx and a manual PackageLayout). It works fine by itself and installs & runs my app without issue (a C++ FullTrust UWPDesktop app).
However my app previously was just a simple Windows C++ application and shipped using an .msi-based installer. The same installer was used for both first install & build-over-build upgrade.
I want the next release of my app to go out with the .msix instead.
This is fine for all new users but how do I upgrade my existing users from the .msi to the .msix based installer? Currently if I try to "upgrade" from .msi to .msix it causes two versions of the app - the old .msi version and the new .msix. I suppose I need to get the .msix install to remove the old .msi version of the app?