Recently 50 outbound relays were deployed in Dallas to compliment our existing relays in London, using fresh IP space to balance the load between two unique ranges. Due to an internal mistake on our part, these relays have been down since Dec 25th.
Customers will have seen no impact on this at all, this is entirely transparent and only impacts routing switches on our back-end. This update better serves as a timeline for background context on the underlying infrastructure.
All email continues to go through our IP space, and then through MailChannels if our IP's are rejected by the recipient server.