[imp] Error in upgrade documentation?

[Patrick Boutilier]

imp/docs/UPGRADING starting at line 141:

Removed Preferences
-------------------

The following preferences are no longer used and may be safely removed from
your ``config/prefs.php`` file and your preferences backend::

    'disposition_request_delivery'
    'disposition_send_mdn'
    'wrap_width'



Isn't 'disposition_send_mdn' still used for sending read receipts from IMP?