MySQL HeatWave on AWS supports the most recent release version of MySQL.
Minor versions, such as 8.0.nn, must be applied manually. See Upgrade MySQL Version for information.
Upgrade versions, such as 8.0.nn-un, are applied automatically and according to the maintenance window defined on the DB System.
For more information about MySQL Server versioning, see Server Versioning.
It is not possible to roll back (downgrade) an upgrade. It is recommended to perform a full backup before upgrading your DB System.