Backing up and Importing IMAP folders

[Konstantin Khomoutov]

On Thu, 20 Oct 2016 16:57:45 +0300 (EEST)
Aki Tuomi <aki.tuomi at dovecot.fi> wrote:

[...]
> > Alternatively you can use `dsync` to perform backup with a native
> > Dovecot tool.  It's able to sync mailboxes of any Dovecot user --
> > including synchronizing a mailbox to an empty (yet) spool.
> > You'll need to do a bit of shell scripting which would spin around
> > calling `doveadm user *` and feeding its output to something like
> > 
> >   while read user; do \
> >     dest="/var/backup/dovecot/$user";
> >     mkdir -p "$dest" && chown vmail:vmail "$dest" \
> >       && chmod 0755 "$dest"
> >     dsync -u "$user" backup "maildir:$dest" \
> >   done
> > 
> > Note that you will only need this if you don't want to shut down
> > Dovecot to copy its mail spool out.
> 
> You can also use doveadm backup -A maildir:%u/

Looks like `doveadm` of my Dovecot 2.2 (Debian 8.0 Jessie) does not
support the "backup" subcommand.  Is it a past-2.2 addition?