Ticket #34224: 34224.patch

src/wp-admin/includes/upgrade.php

@@ -2631 +2631 @@
 
         // Upgrade versions prior to 4.4.
         if ( $wp_current_db_version < 34370 ) {
-                // If compatible termmeta table is found, use it, but enforce a proper index.
+                // If compatible termmeta table is found, use it, but enforce a proper index and update collation.
                 if ( $wpdb->get_var( "SHOW TABLES LIKE '{$wpdb->termmeta}'" ) && $wpdb->get_results( "SHOW INDEX FROM {$wpdb->termmeta} WHERE Column_name = 'meta_key'" ) ) {
                         $wpdb->query( "ALTER TABLE $wpdb->termmeta DROP INDEX meta_key, ADD INDEX meta_key(meta_key(191))" );
+                        maybe_convert_table_to_utf8mb4( $wpdb->termmeta );
                 }
         }
 }