problem with lda

[Infoomatic]

Hello,

I am currently testing the upgrade from our dovecot v2.2.23 to 2.3.0. I have a strange problem with lda.
We use bounce mails for internal users if they try to send virus/spammails. The exact same config works with 2.2.23, but not with 2.3.0.

The relevant postfix/master.cf part:
dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/opt/dovecot/libexec/dovecot/deliver -d ${recipient} -f ${sender}

On the same machine, with 2.2.23 I get a bounce mail when trying to send a virus, with the subject "VIRUS in message apparently from you (Eicar-Test-Signature)", to both the users inbox as well as to the mailbox of virusalert at ourdomain.internal

With 2.3.0, in the logs I get an error:

relay=dovecot, delay=0.01, delays=0/0/0/0, dsn=5.3.0, status=bounced (command line usage error. Command output: lda: Fatal: Invalid -f parameter: Missing domain 

and the alert message is only sent to virusalert at ourdomain.internal, but not to the user who tried to send the mail.

The relevant part of our dovecot.conf:
protocol lda {
  mail_plugins = " quota zlib sieve acl mail_log notify"
  postmaster_address = postmaster at ourdomain.internal
}

Does anyone know how to solve this problem? Or is there a workaround via postfix/amavis/spamassassin? Any hints are highly appreciated, thanks!

Regards,
infoomatic