Additional informationIn CourierIMAP, maximum length of IMAP folder's name is 254 symbols. In Dovecot, maximum length of IMAP folder's name is 200 symbols.
If you plan to migrate the existing single-host or clustered QMail from CourierIMAP to Dovecot, before the migration make sure that names of IMAP folders are shorter then 200 symbols. You may rename IMAP folder if it is required. Otherwise, IMAP folder cannot be renamed/moved after migration.
See Issue POA-54342.