"strategy" property in @Field annotation is not recognized

@Collection(strategy="set")
works fine

but
==========================================

@Field(type="collection", strategy="set")
causes error:
Fatal error: Uncaught exception 'BadMethodCallException' with message 'Unknown property 'strategy' on annotation 'Doctrine\ODM\MongoDB\Mapping\Field'.' in /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Annotation.php on line 77

BadMethodCallException: Unknown property 'strategy' on annotation 'Doctrine\ODM\MongoDB\Mapping\Field'. in /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Annotation.php on line 77

Call Stack:
0.0007 691072 1.

() /projects/tbi_doctrine/lab/doctrine/insert.php:0
0.0808 6313168 2. Doctrine\ODM\MongoDB\DocumentManager->persist() /projects/tbi_doctrine/lab/doctrine/insert.php:34
0.0809 6313168 3. Doctrine\ODM\MongoDB\UnitOfWork->persist() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/DocumentManager.php:338
0.0809 6313248 4. Doctrine\ODM\MongoDB\DocumentManager->getClassMetadata() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/UnitOfWork.php:1177
0.0809 6313248 5. Doctrine\ODM\MongoDB\Mapping\ClassMetadataFactory->getMetadataFor() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/DocumentManager.php:250
0.0809 6313248 6. Doctrine\ODM\MongoDB\Mapping\ClassMetadataFactory->loadMetadata() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/Mapping/ClassMetadataFactory.php:165
0.0957 6734784 7. Doctrine\ODM\MongoDB\Mapping\Driver\AnnotationDriver->loadMetadataForClass() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/Mapping/ClassMetadataFactory.php:221
0.0978 6669016 8. Doctrine\Common\Annotations\AnnotationReader->getPropertyAnnotation() /projects/tbi_doctrine/vendors/doctrine/odm/lib/Doctrine/ODM/MongoDB/Mapping/Driver/AnnotationDriver.php:182
0.0978 6669016 9. Doctrine\Common\Annotations\AnnotationReader->getPropertyAnnotations() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/AnnotationReader.php:216
0.0979 6669392 10. Doctrine\Common\Annotations\Parser->parse() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/AnnotationReader.php:201
0.0983 6678712 11. Doctrine\Common\Annotations\Parser->Annotations() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Parser.php:209
0.0983 6678928 12. Doctrine\Common\Annotations\Parser->Annotation() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Parser.php:270
0.0986 6680200 13. Doctrine\Common\Annotations\Parser->newAnnotation() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Parser.php:349
0.0986 6680840 14. Doctrine\Common\Annotations\Annotation->__construct() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Parser.php:536
0.0986 6681624 15. Doctrine\Common\Annotations\Annotation->__set() /projects/tbi_doctrine/vendors/doctrine/common/lib/Doctrine/Common/Annotations/Annotation.php:0