Amazon Aurora MySQL: version 8.4 end of standard support

AWS states that a major version can keep running past its standard support end date under RDS Extended Support, for an additional cost. The release calendar lists Extended Support dates and eligible minor versions; some are "To be determined".

• Aurora automatically enrolls a DB instance after that date if RDS Extended Support was enabled at creation or restoration.
• It provides security updates for critical and high CVEs, bug fixes for critical issues, and support cases.
• Charges apply only to certain minor versions.
• Enrollment can be changed at any time, at the cluster level. Disabling it after that date upgrades the instance or cluster automatically to the next supported major version.

1. Look up your type and version of cluster in Aurora MySQL major version upgrade paths. The table says whether the cluster can use the in-place upgrade mechanism and which action applies.
2. Where the table points to a major version upgrade, plan it with Planning a major version upgrade for an Aurora MySQL cluster. A major version upgrade needs more planning and testing than a minor version upgrade.
3. Before an in-place upgrade, create a clone of the original cluster, perform an in-place upgrade of the clone immediately after creating it, and test application compatibility, performance and administration procedures on it.
4. When the test cluster works properly, perform the in-place upgrade for the production cluster. See How to perform an in-place upgrade.
5. If an immediate switchover matters most, run the old and new clusters side by side with Amazon Aurora Blue/Green Deployments.