The MX team will take MX offline to roll-out new functionality or perform upgrades / bug fixes.
​
Updates tend to be the last Wednesday of the month and will take place after 17:30 UK time (UTC / UTC +1), to minimise impact to users.

When a critical vulnerability / bug is discovered, we will sometimes need to take MX down at very short notice.

When MX comes back online, it is a good idea to clear your browser cache.