Upgrading From Previous Versions

Upgrading from a previous 2.0 version

    Warning: You do not need to follow these instructions if you're
    upgrading from version 1.6. 

      * 
        You can now pick whether to use Berkeley db to store seen state,
        the subscription files, and the mailboxes file or a flat text file,
        at compile time only. (Look in imap/seen_db.c and imap/mboxlist.h.) 
      * 

        The format of the mailboxes file and seen state has changed. It is
        not possible to preserve seen state, but upgrade the mailboxes file
        as follows: 

         1. Run ctl_mboxlist -d > mboxlist.temp to dump existing mailboxes. 
         2. Remove old database files: rm mailboxes.db db/* user/*/*.seen 
