We are working hard to ensure that there is minimal impact on message delivery.
If you have a Developers Central or Communicator account, we advise that you do not send or schedule outgoing messages during the maintenance window on 22 April 2018 07:00 - 09:00 (GMT+2). During the maintenance window, there will be a downtime period when no messages will be accepted or queued by our APIs. You will also not be able to login during this time.
Incoming messages will be queued by the network operators and processed as soon as the system is back up and running again. This will result in delays delivering incoming messages via callbacks.