Hi,
I need to tweak these variables in my Rabbitmq :
heartbeat_timeout_threshold
heartbeat_rate
heartbeat_interval
When I tried to add 
heartbeat_timeout_threshold = 600 to rabbitmq.conf and reconfigure, the service failed to start with :

13:39:41.756 [error] You've tried to set heartbeat_timeout_threshold, but there is no setting with that name.

13:39:41.758 [error]   Did you mean one of these?

13:39:41.838 [error]     socket_writer.gc_threshold

13:39:41.838 [error]     handshake_timeout

13:39:41.838 [error]     auth_http.http_method

13:39:41.838 [error] You've tried to set heartbeat_rate, but there is no setting with that name.

13:39:41.838 [error]   Did you mean one of these?

13:39:41.888 [error]     heartbeat

13:39:41.889 [error]     cluster_name

13:39:41.889 [error]     channel_max

13:39:41.889 [error] Error preparing configuration in phase transform_datatypes:

13:39:41.889 [error]   - Conf file attempted to set unknown variable: heartbeat_rate

13:39:41.889 [error]   - Conf file attempted to set unknown variable: heartbeat_timeout_threshold

How can I modify those variables?

Regards.