[knot-dns-users] Setting up zone file MX record to external mail server

Hi, we've had knot in use for years now and are still using version 1.6.7. I We've recently migrated e-mail to exchange online. I've been asked to update the MX record in the zone to point to mail.protection.outlook.com. I initially tried to simply replace the current value by mail.protection.outlook.com but then the name of the zone is added to the value. This is not a valid record. I see no way to update the MX record to this value. Any suggestions? Thanks in advance for the feedback. Kind regards, Dirk