A new constant RUNKIT_OVERRIDE_OBJECTS was introduced. Use it by bitwise adding to the flags parameter of functions runkit_default_property_add and runkit_import to add (and remove) properties of existing objects. This feature works in PHP 5.x and above and it is switched off by default.
New (the third one) parameter remove_from_objects of boolean type was introduced in runkit_default_property_remove function. Pass the TRUE value to remove property from existing objects. This feature works in PHP 5.x and above. The default value for this parameter is FALSE.