SCU - consent to Choice implementation changes

I’ve trawled the documentation but could not find a definitive answer…

When the implementation of a Choice is altered via SCU, is that automatically utilised when parties access it? Are parties made aware of the change? Can they block it pending consent being granted?

When the implementation of a Choice is altered via SCU, is that automatically utilised when parties access it?

The altered Choice body is compiled into a new DAR. The controller of the Choice cannot exercise the new version of that Choice until all the stakeholders on the existing contracts have uploaded the new DAR to their hosting participant node.

Are parties made aware of the change?

The publisher of the DAR tells app users off-chain, “We have a new version of the DAR. Please upload and vet it.”

Can they block it pending consent being granted?

They can decide not to upload or vet the new DAR.

That’s how it works today.

So, the controller of the participant node decides when to deploy it, and all parties hosted on that node must use it? There is no indication to them?

The DARs are uploaded and vetted to the node by the operator, yes. There is no way to limit the DAR vetting to specific parties.

There is no builtin way to provide an “indication” to the parties (or the entities they represent).

In short, the entities represented by the parties trust the node operators.

Ok. Thanks for the clarification.