Doveadm Backup Error

Greetings,

On 2.3 I was able to run the following command, but now on 2.4 I'm getting the following error:

doveadm backup -u user@domain.tld maildir:/mnt/backups/daily/domain.tld/user

dsync(user@domain.tld): Error: brain M: Exporting mailbox INBOX failed: Mailbox attribute iteration failed: Mailbox attributes not enabled

So, I tried to set the configs to include:

protocol imap { imap_metadata = yes ... }

mail_attribute { dict file { path = %{home}/dovecot-attributes } }

But then I get:

Error: brain M: Exporting mailbox INBOX failed: Mailbox attribute iteration failed: BUG: Unknown internal error

Can anyone clarify the proper configs for this?

Thank you,

Asai