[Mimedefang] MUA tracking?

[Josh Kelley]

I'm interested in gathering statistics on which MUAs our users use (so
we can find out what mail clients are popular enough to officially
support, which old clients we can drop support for, who's using old
versions and should be gently encouraged to upgrade, etc.).  I figure
that MIMEDefang can track this by grabbing the X-Mailer: header of
messages as they go through, and I thought that I'd ask the list to
see if anyone's already done this before I go write some code.

Alternatively, would there be a better way of doing this?

Josh Kelley