Over the next month, we will migrate Blizzard, Sunfire, Pixel, and Echo servers. Each of these servers was deployed with a flaw that will cause excess downtime soon, and we are migrating them to new hardware to prevent customers from having to experience downtime. These migrations will be scheduled where possible, so long as we beat the upcoming downtime event (which we cannot accurately predict a time or date for). Email notices will be sent out to customers on these servers as relevant. So long as we beat the downtime event, users should not experience downtime.
All of your DNS records must point to our servers using a CNAME record, not an A record. The IP of each server will change. This is why we always recommend CNAME records instead of A records.