I intend to do two server tasks this Thursday afternoon.
1: Do a dist-upgrade from Debian Stretch to Debian Buster.
2: Upgrade from PHP7.0 to PHP7.3.
Therefore Hubzilla at elsmussols.net, nextcloud.elsmussols.net and email will be down from about 1300CEST (1100UCT) 1500CEST (1300UCT) on Thursday, 01 August 2019. I hope to be down for a maximum of three hours.
update: timeframe moved two hours later (can't turn down paid work).