iOS 6.1 problems

Since updating my iPhone 5 to 6.1 I can no longer use Navigon in conjunction with Siri. As soon as I use Siri I lose my turn by turn audible announcements. If I reboot Navigon completely it will start working again. I can still play music but cant use Siri.

Glenh2nd about NAVIGON U.S. West, v2.3