Discussed in Prague meeting. This should not be worked on until we have a confirmed use case and one or more vendors willing to implement it.

One of the goals for public groups is to minimize the size of data change events. When receiving an event for a group, since the members of the group are known in advance, it is not necessary to include a client handle for each item. Instead, you only need to include a client handle for the group. Consequently, I think that solution 2 is preferred. See attached doc that describes the IEC 61850 data change event contents.

The reason for a client handle is not the "client private" subscription. The reason is that the server sends only values for monitored items that did change. You are asking for a subscription that is sending a value for all monitored items independent of their change status.

The size of data change would only be minimized if more than 50% of the values always change.

This feature is covered by the PubSub functionality.

Servers can be configured to Publish DataSets to a middleware (e.g. MQTT broker or UDP multicast group) and all Subscribers can subscribe from the middleware.

Agreed this was implemented in 1.04