I quote https://learn.microsoft.com/en-us/windows/apps/design/app-settings/store-and-retrieve-app-data

Storing app data in the app data stores

...The system also preserves the contents of these data stores when the user installs an update to your app...

However I have demonstrated that after performing an update of my app via the Microsoft Store the data in ApplicationData.Current.RoamingSettings is wiped.