How to temporarily make all mailboxes read-only for backup purposes?

Dear all,

I am using Dovecot sdbox format for mailboxes. Is there an option to temporarily make Dovecot read-only while the mailboxes are being backed-up such that a consistent state is backed-up?

I am looking for some command which I can use as pre- and post-hook for Borgbackup. I am looking for a way such that Dovecot defers any mail coming in via LMTP from Postfix, denies modifying mails/mailboxes via IMAP while Dovecot still allows to browse mails read-only.

Is that possible?

Bests, Matthias