In March, we announced that we would have a preview to support AMP for email in Outlook.com by summer. Today, we are happy to announce that we have entered the developer preview phase. Support for the format has been rolled out but it is turned off by default. Any email sender interested in trying their AMP emails in Outlook.com can turn it on for their mailbox for testing purposes.
Additionally, senders can register now to send AMP emails to their customers in the near future.
To learn more, visit the Microsoft Outlook Dev Center.
Source: Developer preview of AMP for email in Outlook.com