Dovecot supports the IMAP METADATA extension (RFC 5464), which allows per-mailbox, per-user data to be stored and accessed via IMAP commands.

To activate metadata storage, a dictionary needs to be configured in the Dovecot configuration using the mail_attribute_dict option.

To activate the IMAP METADATA commands, the imap_metadata option needs to be activated.


# Store METADATA information within user's Maildir directory
mail_attribute_dict = file:%h/Maildir/dovecot-attributes

protocol imap {
  imap_metadata = yes