Hi Francesco,

SDK is not designed in a way that you should modify the returned DataValue. I’m not sure can we change DataValue to be truly immutable, but it should be assumed to be as such (except in e.g. IoManagerListener where the whole API is designed so that you modify the DataValue given as parameter to the listener methods). This includes that you cannot modify any value you have given as value afterwards. Though, SDK automatically clones the DataValue to be sure, but the getValue doesn’t clone (it probably should, but I’m not sure of the perf implications so we might be unable to do that).

Basically our design relies on the UaNodes telling the items that their value has changed (the item registers a listener to the node). But if you mutate the DataValue directly, SDK has “no way of knowing” this happened, thus there is no knowledge of the change. The initial value for the item is read differently, thus that is why it appeared to work for new subscriptions.

Thus, you must always use the ‘setValue’ methods. You should be able to use null for the value or use setValue(new DataValue(StatusCode.valueOf(StatusCodes.Bad_DataUnavailable)))’ if you just want to set the statuscode (basically the non-DataValue overrides of ‘setValue’ just make DataValues internally). Then they should update always for existing subscriptions.