KIP-1155 — Metadata Version Downgrades

Discussion KRaft

Introduces metadata version downgrade support, allowing a KRaft cluster to roll back its MetadataVersion to an earlier value after a failed or undesirable upgrade. Currently, MetadataVersion is a one-way ratchet—clusters can upgrade but never downgrade—meaning operators who encounter bugs in a new metadata version have no recovery path short of a full cluster rebuild.

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