[Dovecot] Marking messages read / retaining date with Sieve

[Bret Martin]

I'm trying to mark several hundred thousand messages as read as they are delivered via dovecot-lda(1). (I'm importing some mail from another format for migration purposes.)

I've been able to do this with Sieve, but it has the side effect that the messages' received and saved dates are set to the current date, and Apple Mail (at least) uses one of these to display the message date. Without the Sieve filter in place, the dates are retained based on the From_ line as I would like.

Does anyone know of any way I can either

- retain the date when delivering using Sieve?

- systematically mark a specific set of messages as read *after* delivery instead, perhaps with doveadm(1)?
  (even marking *everything* read would work in this particular case. I couldn't find any way to set flags with doveadm)

Thanks,

--Bret