There will be a maintenance window next thursday 14:00-15:00 CEST (Berlin time). The actual downtime should be just around 10 minutes within that time frame.
We will migrate all sandbox databases to a new dedicated server hosted on SoftLayer. This migration should not have any negative impact on the performance or availability.
As usual, if you run into any issues or if you have any questions please get in touch with us at firstname.lastname@example.org.