isync: free IMAP and MailDir mailbox synchronizerisync is a command line application which synchronizes mailboxes; currently Maildir and IMAP4 mailboxes are supported. New messages, message deletions and flag changes can be propagated both ways. isync is suitable for use in IMAP-disconnected mode.Synchronization is based on unique message identifiers (UIDs), so no identification conflicts can occur (as opposed to some other mail synchronizers).Synchronization state is kept in one local text file per mailbox pair; multiple replicas of a mailbox can be maintained.isync is free software in the sense of the GNU GPL v2.