KevinTheJedi
First, I found the template! Thank you for that.
As for custom changes, it's possible, since there were customizations set up long before I arrived. I did a search in osTicket files for anything containing "ticket.thread," and the only result was a file named ajax.content.php, under the include folder, with this bit of code:
I'm not sure how that's set up exactly (presumably there's code somewhere else that allows that variable to be used). In any case, I'm trying to find a variable that will allow me to include just the ticket's last reply. For some reason, the %response variable, which is used on the Response/Reply Template, isn't supported in the New Activity Notice template: