We are migrating the server mu22 and all sites hosted on mu22 to a new server on April 4 2019.
The downtime should be of one time around 1.5 hour, and a few interruptions of 5-30 minutes maximum.
Please note that the IP address will change during the migration, which is transparent for most customers with DNS servers are hosted with us.
UPDATE 22:35 UTC: The migration is now complete, dns servers are propagating over the next 1-2 hours. Please open a support ticket if you experience any difficulties from April 5th 2019 01:00 UTC.