Previous Setting: The default value for `retry_interval` was 30 seconds.
New Default: The default `retry_interval` has been changed to 'infinity'.
With this update, EMQX will not automatically retry message deliveries
by default.
Compliance and Compatibility: Aligning with MQTT specification
standards, in-session message delivery retries are not typically
compliant. We recognize that some users depend on this feature, so the
option to configure retries remains available for backward
compatibility.
zmstone