When are updates available?
Scheduled application updates are released multiple times per year. Exact dates are not set in advance. Availability of an update can be checked at any time from the app overview page in the Windows Store app. If you have enabled automatic update downloads in Windows Store settings, you don't need to worry about missing one.
Map updates are in most cases available after the application is updated, although not every application update will also contain new maps. The layout of the Manage Maps screen inside the app will change to only show you the maps you have downloaded previously, and offer the update option (Menu -> Settings -> General tab -> Manage Maps).