There is a backup in the import export tools add-on.

https://addons.mozilla.org/en-US/thunderbird/addon/importexporttools/

Thank you.

I would like something comparable to the old Mozbackup

Paul Walker said

I would like something comparable to the old Mozbackup

Well there is nothing. Certainly not that I am aware of at least. You must be aware Mozilla has never offered a backup tool, ever. And any external tools has to have a lot of checks against the application currently running as that just messes up the backup.

Mozbackup was a troubled product for a long time, offering to back up bits of a profile that could not be restored without other bits that were not in the backup. In many way I am glad it is out to pasture.