First, I did search for this topic. Found two strings where other users had the problem but both times it ended up with a person saying I have no idea why you are getting this error.
1. Running Windows 10, and the most recent stable release of vpilot
2. Have a valid vatsim account and vpilot is connected to the sim
3. I have run both the sim and vpilot in administrator mode
4. every time I try to hit the connect button (just trying to connect as an observer to listen for a while and learn stuff), I get this error, Invalid Protocol Revision, error connecting to voice serve