Version 2.3 of Navigon for iPhone boosts the navigation app with the Glympse location sharing service and Foursquare.
Glympse support provides a way of giving selected people access to live information about your current position and expected time of arrival.
The Foursquare integration allows searching for locations, trending venues and special deals along your route, checking into venues, and viewing personalised points-of-interest suggestions based on your past check-in behaviour.
This version has attracted several negative comments in the App Store. It appears that it may sometimes be necessary to uninstall and reinstall the app before it works properly.
Navigon for iPhone usually costs $69.99, but that's being discounted to $49.99 until February 3 to mark the release of the new version. Existing owners can upgrade at no charge.