This notice has been emailed to the list owners mailing list and operations list, as well as posted on tasks T108099 & T107445.
I've scheduled a mailman downtime window for planned maintainance on Tuesday, August 18th, 17:00–18:00 UTC. During this time, I'll be working the mailman side of the two tasks. Both are involving list renames. The deployments page on wikitech has been updated with this information: https://wikitech.wikimedia.org/wiki/Deployments
I do not expect this work to take the entire window. However, during this time, mailing list traffic will fail to receive/send. Once mailman is restarted, it will process mailing list messages. That means that mailing list delivery may be sporadic, or not at all, during this window. Any messages sent during this time will process either during or directly after the end of the maintenance.