maybe_convert_table_to_utf8mb4 example

if ( is_multisite() ) {
            $tables = $wpdb->tables( 'blog' );
        } else {
            $tables = $wpdb->tables( 'all' );
            if ( ! wp_should_upgrade_global_tables() ) {
                $global_tables = $wpdb->tables( 'global' );
                $tables        = array_diff_assoc( $tables, $global_tables );
            }
        }

        foreach ( $tables as $table ) {
            maybe_convert_table_to_utf8mb4( $table );
        }
    }
}

/** * Executes comments changes made in WordPress 4.3.0. * * @ignore * @since 4.3.0 * * @global wpdb $wpdb WordPress database abstraction object. */