There is a thread with drivers for test, however from feedback more work is needed and this is being looked at, however Puddy suggested the following.
This info is for those who are running windows 8.1 x64
choose airnav windows 7 64bit drivers and go through the directions below
1. From the Metro Start Screen, open Settings (move your mouse to the bottom-right-corner of the screen and wait for the pop-out bar to appear, then click the Gear icon).
2. Click ‘Change PC Settings’.
3. Scroll down, and click ‘update and recovery’
4. Click ‘recovery’
5. Click under advanced start up and restart now
6. Click ‘Troubleshoot’
7. Click ‘Startup Settings’
8. Click Restart
9. When Win8 restarts type the number next to \"Disable driver signature enforcement\"
can be used with windows 7 64bit drivers
works with airnav ver 403
works with airnav ver 5
Puddy