mdbox backup strategy

[Jiří František]

Hi, now we backup maildir with rdiff-backup every single day. Backup takes
almost 20hours. I would like to switch to mdbox, but how to acomplish
possibility of restore emails from any date what I want?
Now if I need to restore mails from the day before yesterday I put the
right date to parametrs of rdiff-backup restore command and I get what I
want.
But if I use doveadm backup I have backup only from last run. Because we
have tens of TB email I couldn't do full backup every single day.
Is it possible to restore state of mailbox from backup run before the last
run if I use doveadm? I don't want do full backup every day, because backup
storage is not unlimited.

Thank you Jiri