[Mimedefang] remove_redundant_html > delete_header?

[Michael Fox]

I’m new to the list so be gentle!

I’m using Postfix with the following milters/filters in this order:
* pre-queue milters:  opendkim, mimedefang  (I plan to add opendmarc after
opendkim)
* post-queue content filter:  amavisd-new (with spamassassin, clamd)

I have an old client that doesn’t understand HTML.  So, I’m using
remove_redundant_html_parts().  And that works great.  But by changing the
message, the DKIM-Signature is no longer going to match.  Since OpenDKIM
runs before MIMEDefang, it is still able to validate the signature.  So far,
so good.

But amavis/spamassassin runs after mimedefang.   So I’m wondering if I
should take further action so that spamassassin doesn’t see a mismatched
signature.
Specifically:
If remove_redundant_html_parts() returns true (it removed HTML parts), then
should I also delete the ‘DKIM-Signature’ header?
And, if I remove the DKIM-Signature header, should I also remove the
“Authentication-Results:” header?
In other words, what’s the best method for keeping all of the players happy?

Any thoughts/wisdom would be helpful.
Thanks,
Michael