I upgraded to Doctrine 2.2 and got following exception:
"Doctrine\Common\Annotations\AnnotationException [Semantical Error] Annotation @version is not allowed to be declared on class SomeEntityClass. You may only use this annotation on these code elements: PROPERTY."
In Doctrine 2.1 no such exception has been thrown. I use following annotation for all my classes in my projects:
@version $Id: SomeEntityClass.php 509 2012-02-03 09:38:48Z mf $
Thus I cannot upgrade to Doctrine 2.2 for now.