PHP5beta3: delete

Hello, i'm checking out new features in php5 as announced in http://www.zend.com engine2/ZendEngine-2.0.pdf . Regarding to page 20 of this document, there is a new method "delete" to destroy an instance of a class. i'm tried this function with <? class Klasse {...}; $obj = new Klasse(); delete $obj; ?> and getting a "parser error on line ...". Seems to me, that "delete" isn't implemented yet/other way implemented? What about the issue "deleting objects/using destructors"? How do I use these features? Ok, and for my future getting infos about php5 changes: where can i get informations about those funcionality issues? (news, mailings, WEBSITES?) Thanks for your help, vivi