3.1.2.2.1 Upgrading MySQL 8.0 BugFix to MySQL 8.4 LTS

MySQL 8.4 LTS introduces some new features and removes some deprecated features as compared to MySQL 8.0 BugFix. Here are some important changes you should be aware of before upgrading your DB system from MySQL 8.0 BugFix to MySQL 8.4 LTS:

• As the default_authentication_plugin variable is removed in MySQL 8.4, the DB system ignores the default_authentication_plugin variable in the MySQL Configuration. It always defaults to caching_sha2_password. You can override the default authentication method of your user accounts with the CREATE USER and ALTER USER statements if needed.
• The deprecated mysql_native_password authentication plugin is disabled by default. Your user accounts cannot use the mysql_native_password authentication method.

  Note:

  For backward compatibility, if the mysql_native_password authentication method is used by any existing users, the upgrade will enable the deprecated mysql_native_password authentication plugin. As the mysql_native_password authentication has been removed in the major versions after MySQL 8.4, you should start to migrate these user accounts to use the caching_sha2_password authentication method.
• These new reserved words are added in MySQL 8.4: MANUAL, PARALLEL, QUALIFY, and TABLESAMPLE. You cannot use any reserved words in unquoted identifiers.
• The AUTO_INCREMENT option is no longer allowed in FLOAT and DOUBLE data types. Upgrade fails if you have a table that contains a FLOAT or DOUBLE column with AUTO_INCREMENT.
• The SET_ANY_DEFINER privilege introduced in MySQL 8.2.0 is granted to the administrator account and administrator role of any DB system running MySQL version 8.2.0 or higher.

Note:

You cannot upgrade MySQL 8.0 to MySQL 9.x directly; you must first upgrade MySQL 8.0 to MySQL 8.4, then upgrade MySQL 8.4 to MySQL 9.x.