...

There are no changes in public interfaces.

Proposed Changes

If Kafka started on java11 compatible environment then 

SslConfigs.DEFAULT_SSL_ENABLED_PROTOCOLS = "TLSv1.2,TLSv1.3"

SslConfigs.DEFAULT_SSL_PROTOCOL = "TLSv1.3"

If Kafka started on java version that is lower java11 then

SslConfigsChange the value of the SslConfigs.DEFAULT_SSL_ENABLED_PROTOCOLS to = "TLSv1.2,"

SslConfigs.DEFAULT_SSL_PROTOCOL = "TLSv1.32"

Compatibility, Deprecation, and Migration Plan

...

Migration: Users who are using TLSv1.1 and TLSv1 should enable these versions of the protocol with the explicit configuration property "ssl.enabled.protocols"

Rejected Alternatives

There are no rejected alternativesWait until java8 gets TLSv1.3 support and made changes afterward.