Here the notice from Serverius NOC about upcoming core network emergency maintenance:
We found a critical bug in our Huawei switches. To avoid any future problems related to this bug, we will have to upgrade our hardware. For the upgrade we should restart the switch to which you are connected. So, we are going to restart this switch at 00:00 18.04.2017. During this maintenance you will have up to 5 minutes of downtime. We apologize in advance for any inconvenience that this might cause.
During this maintenance network access from few of our racks will be unavailable for short time.
Customers with questions or concerns are encouraged to reach out to our Customer Support team.