"Modify" attribute

As I am trying to figure a way to offer subscription changes to my members, I read that the “modify” attribute is now deprecated in Paypal, so the option of 1 or 2 won’t work. However, reading in the Shortcode Attributes section for the Paypal Pro-Forms, it still states that we can use those options. Is it working for forms and not buttons, or is it just a forgotten detail in the Pro-forms instructions that is not updated to mention the deprecated value?