QT Purchasing on Windows works only on Windows RT.

Microsoft now supports 'desktop app converter' and 'MsixTool' to convert any desktop app(including QT apps) to be converted into .appx or .msix packages that can be uploaded to Windows Store. All of this works great with QT Applications with the exception of QT Purchasing.

This seems to be restriction for Windows only. QT Purchasing APIs give error "QInAppPurchaseBackend not implemented on this platform!" Since regular desktop applications can now be converted to .appx and .msix format to be submitted to Windows Store easily, Qt Purchasing should work instead of giving this error.

On MacOS, QT Purchasing works as documented.