...

protocol imap {
  # Space separated list of plugins to load (default is global mail_plugins).
  #mail_plugins = $mail_plugins
  # Django : 2014-08-06 Quota-Informationen via IMAP zur Verfügung stellen
  mail_plugins = $mail_plugins imap_quota


  # Maximum number of IMAP connections allowed for a user from each IP address.
  # NOTE: The username is compared case-sensitively.
  #mail_max_userip_connections = 10
}

...