Many IMAP clients display information about total number of messages/total number of unseen messages in IMAP mailboxes. In order to do that they are forced to issue a LIST or LSUB command, to list all available mailboxes, followed by a STATUS command for each mailbox found. This document provides an extension to LIST command that allows the client to request STATUS information for mailboxes together with other information typically returned by the LIST command. This improve performance on slow links with high latency and save us bandwidth. And its already supported in Dovecot server.