= 5.6 Migration Guide
:toc:

This guide discusses migration from Hibernate ORM version 5.5 to version 5.5.

For migration from other versions, see https://github.com/hibernate/hibernate-orm/wiki/Migration-Guides .

== Known changes

This version is very similar to Hibernate ORM 5.5, with the exception of having removed some long standing deprecated features.

=== Javassist removed

It is no longer an option to choose Javassist as implementation used for the bytecode enhancement of entities.
Byte Buddy has been the default for some time, and Javassist has been deprecated for some time and now has been removed.

This should have no functional impact on applications; the only exception being that it's not longer valid to
configure `hibernate.bytecode.provider=javassist`: remove the property if you're using this.

A side effect is that Hibenate ORM no longer lists javassist among its dependencies.