Yep, I already (sort of) figured that out. See
this post in this very same thread.
Since it was in the general endpointman
functions.inc.php, I didn't think it was brand specific. I didn't see anything related to pjsip notify (or more properly pjsip send notify) anywhere else in that file.
As stated in that post, I know virtually nothing about PHP so I'm at a loss how to add the necessary code/functions to get the commands included. At least I can manually reboot one extension at a time from the CLI.