From the HP Listserv Administrator (Rudy):
Highland Park Neighbors,
During THIS weekend (11/13-11/15) the Highland Park Neighborhood email list will be down for maintenance. There will be a final reminder tomorrow at 3pm, after which no further messages will be accepted before the list is shutdown.
During the maintenance, any mail sent to the list will be held by your mail provider. Due to the length of the outage, you might receive a non-delivery report after a few hours, which should state that the message will be retried again until it is successfully delivered. The best thing to do is to hold off sending any new messages until the maintenance period is over. I will send another message when the list has returned to normal operation.
This work is mostly motivated by the need to update the list software to reverse and avoid problems with mail servers that use/honor the DMARC p=reject option going back to April 2014. If you are interested in further details, just ask.