removal of allow_call_time_pass_reference

Regarding backward compatibility option "allow_call_time_pass_reference" one will find in the php.ini: "... future versions of PHP/Zend are likely not to support it. ...". A customer of mine relies heavily uppon that feature however, be it "wise" to do so or not. He is now a little confused as to how much time he has until support in aspect to backwards compatibility is removed. What I'd like to now is if there is a standard policy how language support regarding backwards compatibility is handled. How long will there be support for deprecated Features like register_globals or allow_call_time_pass_reference? Will they get lost on a whim during a major version change? After all I still see support for those in php5. ./regards Florian