RHEL 8.3 is out, see the official announcement.
The unquestionable highlight from a KVM on Z perspective is certainly the addition of the Secure Execution functionality. Also, ECKD
DASD can be transparently passed through to KVM guests, allowing full
exploitation of all DASD features, including raw track access and IPL
For further details on the changes, see the release notes, and the respective blog entry in the Linux on Z blog here.