O servidor Dovecot IMAP pode fornecer por usuário Sinalizador visualizado em pastas compartilhadas:
Dovecot Maildir: Bandeira por usuário \
With Maildir a dovecot-shared file controls if the \Seen flags are shared or private. The file must be created separately inside each Maildir, although if the file already exists in the Maildir root it's automatically copied for newly created mailboxes. If dovecot-shared file doesn't exist in Maildir, the \Seen flags are shared. If it exists, the \Seen flag state is stored only in the user's index files. By making each user have their own private index files, you can make the \Seen flag private for the users. [...]
If you want to change what flags are shared when dovecot-shared file exists, currently you'll have to modify the source code: src/lib-storage/index/maildir/maildir-storage.c maildir_open() has mbox->ibox.box.private_flags_mask = MAIL_SEEN; Change the MAIL_SEEN to any flag combination you want. See src/lib-mail/mail-types.h for list of valid flags.