Dishnet sent me a final notice saying that my 721 DVR (i own it) will no longer be supported and will lose programing. I called them and they offered to upgrade my receiver for free to a leased 522. I asked why it would no longer work and they could not tell me. Is this true? Does everybody have to upgrade older receivers? Does it have to be leased or can I buy a used one and what will be compatible in the future?