Today, we successfully upgraded all Cloud Demo and Preview instances to our 2019.4 version. Because this upgrade requires downtime, we are scheduling it within a window during non business hours. Your upgrade window depends on what data center your instance is hosted in, and is as follows:
For instances hosted in our Amsterdam data center: May 7th, 2pm-8pm PDT
For instances hosted in our Phoenix data center: May 7th, 7pm-12am PDT
Due to the way our upgrades get batched together, we can't guarantee a specific time that your upgrade will happen (and thus, your instance is down) other than that it will fall in these windows. Let us know if you have any questions about this!