The server change may cause the sites to be in $wgReadOnly mode for 15 to 30 minutes. We should communicate this to editors in advance, using User-notice and other methods.
Do what worked for T129387 in April and May 2016, including:
- Multiple announcements in Tech News
- Simple explanation at https://meta.wikimedia.org/wiki/Tech/Server_switch_2016 to be sent via MassMessage to (nearly) all wikis
- Last-minute warnings via CentralNotice about the impending site outage.
- Post on some mailing lists (e.g., wikitech-l, maybe tech-ambassadors@?) and/or IRC.
- Earlier warning to Outreach/Education people, so that they can avoid scheduling workshops on the likely dates.