Mailbox Formats
See https://doc.dovecot.org/admin_manual/mailbox_formats/
Mailbox formats not supported by Dovecot:
Name |
Description |
UW-IMAP's old high performance mailbox format. One file contains all the mailboxes, so expunges may still be slow. |
|
UW-IMAP's new (2006) high performance mailbox format. Similar to multi-dbox. |
|
A format created by Exim. |
|
One file contains one message. Sort order of the folder determines the message ID and name. Actively used by projects such as MH-E, NMH, exmh. Experimentally supported by UW-IMAP. |
|
Similar to mbox, but instead of From-line separators it uses four ^A characters |
|
One file contains one message, plus there are a couple of index/cache files. Commonly referred to as being maildir-like, although they have only a single thing in common. |
Adding support for new formats for Dovecot isn't very difficult, although it can be time consuming. Dovecot exposes a nice and simple API which needs to be implemented.
Software Support
Format/Software |
|||||||||
Yes |
Yes |
No |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
|
No |
Yes |
No |
Yes |
No |
Yes |
No |
No |
No |
|
Yes |
No |
Yes |
Yes |
Yes |
No |
Yes |
Yes (3.22) |
Yes |
|
No |
No |
No |
Yes |
No |
No |
No |
No |
No |
|
Yes |
No |
No |
No |
No |
No |
No |
No |
No |
|
No |
Yes |
No |
No |
No |
Yes |
Yes |
Yes |
No |
Conversion Between Mailbox Formats
See Migration/MailFormat.
References
Mutt mailbox formats: https://rucus.ru.ac.za/docs/mutt/manual58.html
Article on mailbox formats: https://www.livejournal.com/users/rfunk/1571.html
Mbox and maildir comparison: https://www.linuxmail.info/mbox-maildir-mail-storage-formats/