What's Changed
Added a new behavior.
The ORM now will ignore relations and uninitialized Entity properties. In this case, unset($entity->relation) will not change the relation when saving, and it will hydrate it if the relation is loaded in the query.
To restore the old behavior where the ORM tries to fill all uninitialized relations if the entity is created not through the ORM (using new), and also treats unset as unlinking relations, pass an Options object into ORM constructor with the field $ignoreUninitializedRelations = false.
Full Changelog: v2.10.1...2.11.0-RC1