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There is no backward compatibility problems brought in because we are changing it in a compatible way.

We should pay attention to KAFKA-10140 in which we have a problem updating jmx configs using `incrementalAlterConfigs` but we can still update jmx configs using `alterConfigs`, however, the problem only appear when append/subtract list type config which is not supported by kafka-configs.sh, so it will not influence this KIP, and we leave it in another one when we try to support append/subtract  in kafka-configs.sh.

Test Plan

new client tool with older server can be tested locally and using test cases.

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