Hello.

This is the expected behavior. It does not, however, have much to do with the client side: We simply send you the notifications that the server sends to us - not more, and not less.

In general, the OPC servers are required (by the spec) to send updates for all items after they are subscribed to, and most servers conform with this requirement. So that's why are you getting them.

In fact, this is the first time it looks like somebody has an issue with it, and wants the behavior reversed. Quite commonly, users have complaints of opposite nature: Either they do not receive any update after they established a subscription (e.g. due to a faulty server), or they may be receiving them with a long delay, and ask for some additional notification that would be guaranteed to come quickly after the subscription is made (albeit maybe "just" from the client side).

Can you please explain the use case in which the initial notification is undesirable?

Thank you