anchor.diff:  
   %% return = ok       | wildcard processed
   %%          SipError   db error
  -%% unregister all SipUser entries
  -unregister(LogTag, Header, _SipUser, Locations) ->
  +%% unregister all location entries for a sipuser
  +unregister(LogTag, Header, Locations) ->
       %% unregister all Locations entries
       F = fun() ->
   		unregister_contacts(LogTag, Header, Locations)
  
positive.code: %% REGISTER request had no contact header
  process_updates(_LogTag, _Header, SipUser, []) ->
      %% RFC 3261 chapter 10.3 - Processing REGISTER Request - step 8
      {ok, {200, "OK", [{"Contact", fetch_contacts(SipUser)}]}};
  
  process_updates(LogTag, Header, SipUser, Contacts) ->
      %% Processing REGISTER Request - step 6
  
negative.code: 	    logger:log(debug, "Location: Processing valid wildcard un-register"),
  	    case phone:get_sipuser_locations(SipUser) of
  		{atomic, SipUserLocations} ->
  		    unregister(LogTag, Header, SipUserLocations);
  		_ ->
  		    none
  	    end;
  