Upgrade a Windows UAP app from Windows 8.1 Silverlight Phone

Question

I have a Windows 10 app that is intended to replace and older Windows Windows Phone 8.1 Silverlight app. So if the previous app is already installed and is updated from the store, the new Win 10 uap app will replace it. However, I want to keep some of the Application Settings properties from the Silverlight app and transfer them over to the Windows 10.

My idea was that, when starting the Win 10 app for the first time, I would check for the application settings file that was from the previous 8.1 silverlight and read the desired properties.

I changed my AppxManifest file in the Win 10 app to use same Publisher Id, PhoneProductId and PhonePublisher id as the Silverlight. However, when I run the Win 10 app I get a prompt that my previous silverlight app will be uninstalled first (and hence I would lose the application settings file). Is there a proper way to upgrade from Silverlight 8.1 to Win 10 universal without losing the file?

Answer 1

Update the Silverlight App to migrate user settings from Local to Roaming. Even when the Silverlight App gets deleted the user settings will persist in the cloud for a month or so. Because the UWP will use the same App ID these settings will be available for the UWP app.