| | 9 | Dovecot's documentation [http://wiki2.dovecot.org/Migration/Courier warns] about scenarios where this might happen. A pop/imap server keeps some information about what messages you've downloaded, and what messages you haven't. Part of the transition involves converting this information from `courier format' to 'dovecot format'. We incorporated this conversion step into the upgrade. However, during one upgrade (chavez), we made the mistake of allowing dovecot to start before the conversion was complete. This allowed some members to check email before their mailboxes had been converted; and their mail clients downloaded all messages from the server. |