In a December 24 announcement, Microsoft says that the roll-out of DNSSEC and DANE support in Exchange Online will start in mid-January 2022. Because this is a big change for the Exchange Online infrastructure, Microsoft is using a phased deployment which won’t complete until mid-May. Support for DNSSEC and DANE has been coming for a long time, but it’s good that the extra security which these standards bring will be available to Exchange Online tenants.
https://practical365.com/exchange-online-dnssec-dane/
