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