I just switched to ROS2 foxy and now my parameter events don't work anymore.
I couldn't find any documentation on what could have changed.

Basically I have a parameter blackboard node or param server and some nodes which have a param client with added remote node name of the param server, so they can listen to the param servers changes.

So on the "clients" I call this:

parameterEventSub_ = on_parameter_event(
      [this](const rcl_interfaces::msg::ParameterEvent::SharedPtr event) -> void
      {
        RCLCPP_INFO(logger, "parameterEventSub_: new params: %d", event->new_parameters.size() );

        onParameterEvent(event);  
      });

But since foxy, this doesn't work anymore.
I can see that the parameters are set exactly the same as before (eloquent), only the events are missing.

On the parameter server itself I got callbacks by using add_on_set_parameters_callback but that is a method of the node and not of the parameter client.

Does someone know how this should be done now?

Update 3.10.2020

The param event handling is working without namespaces.
But my nodes run in a namespace and then I get no events.

auto parameters_client = std::make_shared<rclcpp::SyncParametersClient>(node, "/parameter_blackboard");

auto parameters_client = std::make_shared<rclcpp::SyncParametersClient>(node, "/foo/parameter_blackboard");