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David Jacot commented on KAFKA-15989: ------------------------------------- I discussed this with Emanuele offline. The issue was that a consumer with a group id and manually assigned partitions committed offsets. This creates a so called simple (generic) group in the group coordinator. Later the same consumer switched to using a subscription with the new consumer group protocol. It sent an heartbeat request to the group coordinator and the group coordinator denied it. The issue is that the group coordinator does not have any logic to upgrade the simple (generic) group to a consumer group yet. We plan to have a full upgrade/downgrade support between the protocol. In the mean time, it seems that we could handle this case without waiting on it. Basically, when a generic group is empty, we could already replace it by a consumer group in this case. > Upgrade existing generic group to consumer group > ------------------------------------------------ > > Key: KAFKA-15989 > URL: https://issues.apache.org/jira/browse/KAFKA-15989 > Project: Kafka > Issue Type: Sub-task > Reporter: Emanuele Sabellico > Priority: Minor > > It should be possible to upgrade an existing generic group to a new consumer > group, in case it was using either the previous generic protocol or manual > partition assignment and commit. -- This message was sent by Atlassian Jira (v8.20.10#820010)