Closes #19612 and #19633

The kafka_2.11, kafka_2.12, and kafka_2.13 managed dependencies refer to versions of the Kafka broker, which are compiled with Scala 2.11, 2.12, and 2.13 respectively. These dependencies are only used when running an embedded Kafka broker.

kafka_2.13 is new with Kafka 2.4.0.

kafka_2.12 has been the recommended version since Kafka 2.0.1 in November 2018. kafka_2.11 was removed at the recommendation of @garyrussell .

Comment From: garyrussell

FYI; support for scala 2_11 will be removed in the 2.5 kafka clients, (which is scheduled to include KIP-531).

The release is scheduled for late Feb/Mar; although they will likely slip (they normally do).

Unless there are breaking API changes; my plan is to ensure S-K 2.4.x is compatible with the 2.5.x clients; while we can't bump the version in S-K itself, there should be no reason that Boot 2.3 couldn't prescribe the newer client.

If there are breaking changes, and the clients are released before Boot's RC, I will be forced to create S-K 2.5.

@wilkinsona @snicoll Let me know if/how you want to track these possibilities with GitHub issues.

Thanks.

Comment From: wilkinsona

Thanks for the info, @garyrussell. I don't think we need an issue right now. Our semi-automated dependency upgrades will let us keep track of the availability of Kafka 2.5 so I think we can just react and create issues as and when it appears and we have something concrete to do.