Share groups took three releases to mature, and are production-ready in the broker today.
| Release | Status of share groups |
|---|---|
| 4.0 (Mar 2025) | Early access, off by default |
| 4.1 (Sep 2025) | Preview |
| 4.2 (Feb 2026) | Production-ready; RENEW, strict record limits, lag metrics |
| 4.3 (May 2026) | More broker and group settings (KIP-1240) |
On a new 4.3.1 cluster share.version is finalized at 1 (Kafka 4.x and KRaft), so share groups work out of the box. Clients lag behind: Java's KafkaShareConsumer is complete, while confluent-kafka 2.15 (June 2026) labels its ShareConsumer a Preview, warns on every start and lacks RENEW. Delivery is at least once (acknowledgments are not exactly-once, KIP-932), so jobs must be idempotent; a group holds at most 200 members by default.