QuickOPC 2020.2 will have an option to switch to basic polled refresh approach. See kb.opclabs.com/What%27s_new_in_QuickOPC_2020.2 for more information.

Expected release date is 1-3 weeks.

Regards

I will discuss the proposed workaround with the developer and if possible, put it into the upcoming versions (2020.2).
Good news are that we are finalizing one large (unrelated) functionality area, so there in fact might be 2020.2 release in matter of weeks (this is not a promise, though).

Regards

Who has developed the server and what protocol/software is it for?
Why don't you ask them to fix it?

If an attribute in a request is optional, it means that the send may or may not include it. It also means that the server must be ready to handle both situations, unless the specification allows for different behavior on server side. Everything the the specification describes is mandatory for the server unless specified optional. Otherwsie, the specification would be useless.

We do not do specific implementation work for pay.

Regards

Who has developed the server and what protocol/software is it for?

I am hesitant to do extra work on an obsoleted protocol for free just to fix a problem that should really be fixed on the server side. If we decide to do it - which is not sure - it will have to go to next version, not to the existing one. There is no date scheduled for the next version yet.

And it needs to be thought through. It cannot be in instance parameters because multiple instances (if they have Isolated = false) share the same subscriptions. It would have to be in EasyDAAdaptableParameters.

Regards

This cannot be changed in QuickOPC.
AFAIK, all OPC XML-DA servers must support it.