Is it possible to change/add headers to incoming mail?

[Kurt Hackenberg]

On 2020-12-09 05:11, Sam Kuper wrote:

>> procmail is not a good option anymore, and has not been for a while
>> now:
>> https://marc.info/?l=openbsd-ports&m=141634350915839
...
> Maildrop is a popular alternative.


Some more delivery agents are listed in the Wikipedia article below. 
They may not all filter or modify messages.

<https://en.wikipedia.org/wiki/Mail_delivery_agent>

There's also GNU mailutils, which includes tools to retrieve, filter, 
and deliver mail.

<http://mailutils.org/>