From postfix-users  Mon Oct 21 16:13:00 2019
From: Chris Wedgwood <cw () f00f ! org>
Date: Mon, 21 Oct 2019 16:13:00 +0000
To: postfix-users
Subject: Re: Remove duplicate header 'MIME-Version'
Message-Id: <20191021161300.GF27983 () aether ! stupidest ! org>
X-MARC-Message: https://marc.info/?l=postfix-users&m=157167480017003

> Is there a way to remove the duplicate header in Postfix?

it might (should) be possible with a milter

> Alternatively, is it possible to remove the MIME-Version header(s)
> altogether? Would this break the message (or the mail client from
> the recipient)?

it depends, it might break things

if possible i would look to see why you have a duplicate header and
address things there