[Dovecot] Thunderbird 1.5 and messages with no Date: header

[grant beattie]

hi,

some of my Thunderbird users have a minor but annoying problem with
messages that have no Date: header.

these clients use BODY[HEADER.FIELDS (Date)] as the date for
messages. when a message has no Date: header, they display the
date as 01/01/1970 10:00:00 because Dovecot returns empty string.

would it be possible for Dovecot to return INTERNALDATE instead, for
messages that contain no Date: header? I know this is not
*technically* correct, but it's a reasonable best-guess, and better
than returning nothing. perhaps as a client-workaround?

I vaguely recalled a previous message about this, but I couldn't find
it today.

grant.