How subscription based working for operator tenant.
Does it have to be provisioned to customer-tenants ("IotValue Plan) which will trigger notifications in case Time Series Data is received? If yes, it probably has to be provisioned to all of them, isn't it? If yes, this would imply, that all customers of our app have to order the Add on.
Yes, Each tenant is completely isolated from others. The Add-On needs to be provisioned to all of them.
Does it have to be provisioned to "operator" tenant which is hosting the application to be informed?
Yes.
Does it have to be provisioned multiple times for a single capability package or is the Add on valid for all tenants grouped in a capability package?
Yes, Each tenant is completely isolated with others, irrespective of capability. The Add-On needs to be provisioned to all of them/whichever tenant needs notifications.