@Override
    public Iterator<String> getFeatures() {
        return Collections.singleton("jabber:iq:privacy").iterator();
    }
Updates an existing privacy list or creates a new one with the specified items list. The
new list will not become the active or default list by default. The user will have to
send another packet to set the new list as active or default.<p>

Once the list was updated or created a "privacy list push" will be sent to all
connected resources of the user.

@param packet IQ packet updating or creating a new privacy list.
@param from sender of the IQ packet.
@param listElement the element containing the list and its items.
@return acknowledge of success.
xmppserver/src/main/java/org/jivesoftware/openfire/handler/IQPrivacyHandler.java