We have identified some urgent security patches that need to be applied to the hosted exchange servers from Microsoft and we are wanting to do this as soon as possible, we have opened up a maintenance window tonight to get this done. Tonight between 10pm until 12am we will be performing a failover test and applying security updates to the Exchange cluster. From 10pm we expect a small network break of no more that 1-2 minutes to test the system failover and the remaining time will be applying patches to the nodes in maintenance. If you have any problems, please feel free to get in contact with us.