The callback registered for an IDL on_update definition currently only receives the updated value of the server parameter. When the update is performed as the result of a setParameter command, users need to use the following pattern:

 if (auto client = Client::getCurrent()) { 
     ... get the svxCtx or opCtx from client and use it
 }
 return Status::OK();

 Since the update handler is being invoked from a command, we already have a client and an OperationContext for the command, and we should pass that in to the handler.