anchor.diff:              abort_slide(State1, SlideOp2, Reason, true)
       end.
   
  --spec send_delta_ack(SlideOp::slide_op:slide_op()) -> ok.
  -send_delta_ack(SlideOp) ->
  +-spec send_delta_ack(SlideOp::slide_op:slide_op(), NextOp::next_op_msg()) -> ok.
  +send_delta_ack(SlideOp, NextOp) ->
       Pid = node:pidX(slide_op:get_node(SlideOp)),
  -    Msg = {move, delta_ack, slide_op:get_id(SlideOp), {none}},
  +    Msg = {move, delta_ack, slide_op:get_id(SlideOp), NextOp},
       send_no_slide(Pid, Msg, 0).
  -
  -% similar to notify_other/2:
  -% pre: incremental slide in slide op on this node
  --spec notify_other_in_delta_ack(OldMoveFullId::slide_op:id(),
  -        NextSlideOp::slide_op:slide_op(), State::dht_node_state:state())
  -            -> dht_node_state:state().
  -notify_other_in_delta_ack(OldMoveFullId, NextSlideOp, State) ->
  -    Msg = {move, delta_ack, OldMoveFullId, {continue, slide_op:get_id(NextSlideOp)}},
  -    send2(State, NextSlideOp, Msg).
   
   -spec finish_slide(State::dht_node_state:state(), SlideOp::slide_op:slide_op())
           -> dht_node_state:state().
  
positive.code:                                   pred -> succ;
                                    succ -> pred
                                end,
              Msg = {move, slide_abort, PredOrSuccOther, SlideOpId, Reason},
              send_no_slide(NodePid, Msg, 0);
          _ -> ok
  
negative.code:                   NotifyNode::boolean()) -> dht_node_state:state().
  abort_slide(State, Node, SlideOpId, _Phase, SourcePid, Tag, Type, Reason, NotifyNode) ->
      PredOrSucc = slide_op:get_predORsucc(Type),
      % abort slide on the (other) node:
      case NotifyNode of
          true ->
  