How to change auto email's sent-from email address for Appointments+

We installed Appointments plus and set it up... works great. However, users are receiving emails sent from my (the developer's) email address. I edited the admin user account to instead use the site-owner's email address, but the emails are still sent from my email (no user account now uses that email address). I'm guessing Appointments+ sucked in my email address during setup/config, and for some reason isn't changing it when I change the user account email address.

How can we make Appointments+ use the correct email address for sending notifications emails to persons who make appointments?