The Windows Phone 8 SDK provides the MapUpdaterTask which lets the users to update the region map downloaded earlier which can be used for offline usage.
This will launch the Map Settings App which lets the users about the updates to the map (if available).
How to Update Map in Windows Phone 8 Programatically using C#?
Below is a sample code snippet demonstrating how the user can download the Map in WP8.
MapUpdaterTask task = new MapUpdaterTask(); task.Show();