The question is simple, what is the difference between those two guarantees in Kafka Streams?
processing.guarantee: exactly_once / exactly_once_beta
Docs says
Using "exactly_once" requires broker version 0.11.0 or newer, while using "exactly_once_beta" requires broker version 2.5 or newer. Note that if exactly-once processing is enabled, the default for parameter commit.interval.ms changes to 100ms.
But there's nothing about difference.