MBOX-Line: From janssen at parc.com  Mon Apr  9 09:33:50 2007
To: imap-protocol@u.washington.edu
From: Bill Janssen <janssen@parc.com>
Date: Fri Jun  8 12:34:39 2018
Subject: [Imap-protocol] thread computation algorithms and Exchange
Message-ID: <07Apr9.093358pdt."57996"@synergy1.parc.xerox.com>

I'm looking at the issues of supporting THREAD, and looking at
http://tools.ietf.org/wg/imapext/draft-ietf-imapext-sort/, there
appear to be two algorithms, ORDEREDSUBJECT and REFERENCES.
REFERENCES includes a flavor of ORDEREDSUBJECT as an element of its
algorithm.

I'm looking at a collection of email mostly sent from Exchange
servers, and notice that it by and large does not support the
"References" or "In-Reply-To" headers, but does always contain headers
called "Thread-Topic" and "Thread-Index".  The "Thread-Index" field
seems to contain a BASE64 string which contains the "Thread-Index" of
its parent message as a prefix.

Has anyone tried to understand or reverse-engineer this Exchange
information to describe a thread computation algorithm that works
better for messages with this information?

Bill

