Service Disruption Notice
Use this status-page style notice while an outage or slowdown is affecting customers. It opens with an Investigating label, lists what is affected, when it started and when the next update is due, and links to your live status page. Replace the sample services and start time with your incident details, then send a follow-up once service is restored.
Loops
Include the next update
Set an owner and a time for the next update before sending. Link to a status page that can stay current after the inbox copy becomes stale, and avoid promising a resolution time you cannot support. Send it as transactional email, not a marketing campaign, even when it goes to every customer. Unsubscribed contacts still receive transactional email, and a service notice is classified by its purpose, not its audience size.