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Version-specific breaking changes for ClickHouse Private components. Review this page before upgrading.

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clickhouse-server version 26.2.1.704 — Server-managed S3 credentials disabled

Starting with clickhouse-server 26.2.1.704, the s3_allow_server_credentials_in_user setting is disabled for security reasons. This change was backported to 26.2 following incidents in which this default caused unintended credential exposure. The operator must be updated before upgrading the server to this version or later. Upgrading the server without first rolling out the updated operator can cause bucket access issues. Action required:
  1. Upgrade the operator to the version shipped with the 2026-09-17 release (or later) before upgrading clickhouse-server.
  2. After the operator rollout completes, proceed with the server upgrade.
If your workloads rely on server-managed S3 credentials via s3_allow_server_credentials_in_user, you must switch to explicit credential configuration before upgrading.

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helm/onprem-clickhouse-cluster version 1.1.245 — Shared Catalog and Stateless Servers enabled by default

Starting with chart version 1.1.245, featureFlags.enableSharedCatalog and featureFlags.disableMetadataPersistentVolumes default to true. New installations will use Shared Catalog, backed by the Shared database engine, and stateless Server nodes out of the box. New installations require no action — the new defaults apply automatically. Existing installations not yet on Shared Catalog must explicitly set the previous defaults to avoid an unintended migration on upgrade:
When you are ready to migrate, follow the Migrate to Shared Catalog guide. Existing installations already on Shared Catalog require no action — the new defaults match your current configuration. On Shared Catalog, DDL that carries an ON CLUSTER clause can be rejected. Remove the clause from your applications, migration scripts and automation. Shared Catalog applies DDL across the whole instance on its own, so nothing replaces it. See Remove ON CLUSTER from DDL queries.

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helm/onprem-clickhouse-cluster version 1.1.210

Starting with chart version 1.1.210, new config constraints are included by default. If you are using a ClickHouse server version lower than 25.10, you must exclude these constraints by adding the following to your server configuration:
Without this configuration, ClickHouse will fail to start as these settings are not recognized by versions prior to 25.10.
Last modified on September 23, 2026