Voicemail email subject line and body

Are the email subject and body changable per email account? I am currently using the realtime DB backend for voicemail. I do see some setting that is in the “general” section of the voicemail.conf in the db which means (I guess) configuratble per mail box (e.g. attach, servermail). What about the subject line and body? Can I add 2 more column in the “voicemail” table and make it customizable per mail box?

As far as I know you can only change that in the source code.

Someone wrote this for an older version of Asterisk once but I can’t find it.