OPC-UA subscription and event notification

I’m connecting to a prosys OPC-UA demo server and I’m defining OPC TAG.
It is not clear from the manual if I’m realizing a subscrition to the OPC-UA node (i.e. I’m notified only when the value changes) or the node is polled.

Besides, the OPC-UA demo server is sending alarm, but I can not see them in IGNITION. How can I subscrive and receive server event in ignition?
Please note that the simple OPC-UA client in ignition is able to subscribe and receive alarm and notification.

If you’re in the designer and you drag and drop a tag from the OPC browser, that’s using a subscription (unless the scan class is in OPC Read Mode).

If you’re in the quick client on the gateway web page then clicking the [s] button next to each node will subscribe to that node for the duration of your web session.

Alarms and events are not supported in either context.

Thanks for your fast and clear answer.