Hi .DotF,
There isn't a built in way to query this. The store app will let the user know that there is an update available and offer to install the update.
If you want your app to detect this and require the update then you will need to track it yourself. If you have a web service for your app you can have the web service report the latest version uploaded to the store. Your app can check this to see if there
is a newer version and inform the user. If it is a minor update and the old version of the app will still work then it can let the user continue without updating, or if it is a major update and the old version of the app won't work then it can require that
the user update. See
Linking to your app for information on how to use the ms-windows-store protocol to open the store to your app's page.
--Rob
