By setting the additional security flag “Prevent older AB Tutor programs from connecting to your remote machines” on your clients, any tutor program not running the same version or above will not be able to connect to the client machines.
The clients will have the status of “Invalid Connection Password” and the warning message will be seen within the status window.
(Scroll down, if necessary).
You will be unable to connect to your clients until you upgrade your tutor program to the same or higher version.