As per 5.0 migration guide https://github.com/hibernate/hibernate-orm/blob/5.0/migration-guide.adoc the default value for hibernate.jdbc.batch_versioned_data property is true. But the user guide http://docs.jboss.org/hibernate/orm/5.0/userGuide/en-US/html_single/ still shows it as false. This needs to be updated.
The new User Guide states now that:
Some JDBC drivers return incorrect row counts when a batch is executed. If your JDBC driver falls into this category this setting should be set to false. Otherwise it is safe to enable this which will allow Hibernate to still batch the DML for versioned entities and still use the returned row counts for optimistic lock checks. Since 5.0, it defaults to true. Previously (versions 3.x and 4.x), it used to be false.