I have been looking for this option but have not been able to find it.
Look at your 'Setup - Techs - Tech Groups - 'Tech Group Levels' and the Default Selected E-Mail Recipients - you also need to ensure that Request Types are assigned to that Tech Group.
If that does not work, might try an Action rule on any update to the ticket. There is a criteria for "Last Update Trigger" and condition of "E-Mail from a Client" and then you can email your techs from that maybe? I have never tried that one.
THANK YOU! I also found some more personal settings while clicking around under Tech > My Account > Notifications that did a similar thing but that I like better because it doesn't sent an email to myself when I update the ticket.