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• org.apache.kafka.coordinator.group.GroupCoordinatorConfig.GROUP_COORDINATOR_REBALANCE_PROTOCOLS_CONFIG

Proposed Changes

• Deprecate group.coordinator.rebalance.protocols in 4.3. The node will log a warning if the configuration is used.
• Remove group.coordinator.rebalance.protocols in 5.0.

Compatibility, Deprecation, and Migration Plan

• Operators using group.coordinator.rebalance.protocols should migrate to the feature versioning system using kafka-features.sh to control GroupVersion, StreamsVersion, and ShareVersion.
  Documentation will provide the mapping between configuration values and equivalent feature flag settings.
• Operators should review their current group.coordinator.rebalance.protocols settings, determine the equivalent feature flag settings for GroupVersion, StreamsVersion, and ShareVersion, then use kafka-features.sh to configure cluster-wide feature levels. After setting feature flags, the deprecated configuration can be removed from broker configuration files.
• What impact (if any) will there be on existing users?
• If we are changing behavior how will we phase out the older behavior?
• If we need special migration tools, describe them here.
• When will we remove the existing behavior?

Test Plan

Describe in few sentences how the KIP will be tested. We are mostly interested in system tests (since unit-tests are specific to implementation details). How will we know that the implementation works as expected? How will we know nothing broke?

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