As of MySQL 8.0.16, the server performs all tasks previously handled by mysql_upgrade. Although upgrading remains a two-step operation, the server performs them both, resulting in a simpler process.and
Because the server upgrades the Performance Schema, INFORMATION_SCHEMA, and the objects described in step 2 as of MySQL 8.0.16, mysql_upgrade is unneeded and is deprecated as of that version, and will be removed in a future MySQL version.and last this
As of MySQL 8.0.16: Start the server with the --upgrade=NONE or --upgrade=MINIMAL option.is mentioned in the second last link.
mysqld --upgrade=MINIMAL
Just follow the recommended upgrade procedure (which has not changed for a while ;) )
https://dev.mysql.com/doc/refman/8.0/en/upgrading.html
https://dev.mysql.com/doc/refman/8.0/en/upgrade-before-you-begin.html
https://dev.mysql.com/doc/refman/8.0/en/upgrade-paths.html
https://dev.mysql.com/doc/refman/8.0/en/upgrading-what-is-upgraded.html
https://dev.mysql.com/doc/refman/8.0/en/upgrade-prerequisites.html
The short version.
Backup the whole database <- VERY IMPORTANT
Upgrade binaries then issue mysql_upgrade with recommended options (see links above).
Regards,
Tomas Helgi