Php/docs/migration54.extensions-other
From Get docs
Other changes to extensions
Changes in extension behavior, and new features:
- mysqli - mysqli_result now implements Traversable
- pdo_mysql - Removed support for linking with MySQL client libraries older than 4.1
- The MySQL extensions mysql, mysqli and PDO_mysql use mysqlnd as the default library now. It is still possible to use libmysqlclient by specifying a path to the configure options.
- mysqlnd - Added named pipes support