# Example of a Multi-Version Upgrade This example walks through a common scenario. It moves from an older CFK with a ZooKeeper-based Confluent Platform to the latest CFK with a KRaft-based Confluent Platform 8.x. Use it as a template. Your exact versions can differ, but the order and the reasoning are the same. Before you follow this example, read [Upgrade Confluent Platform Using Confluent for Kubernetes](co-upgrade-overview.md#co-upgrade-overview) and choose your own upgrade path using the same reasoning. **Starting point** CFK 3.1 with Confluent Platform 7.3, running in ZooKeeper mode, using classic Control Center (Legacy). **Target** CFK 3.3 with Confluent Platform 8.3, running in KRaft mode, using Control Center. **Why this path has multiple jumps** The path is not a single upgrade because of the constraints mentioned in the [Before you choose your upgrade path](co-upgrade-overview.md#co-upgrade-before-choose-path) section. In this scenario: - CFK 3.3 requires at least Confluent Platform 7.5. Because the starting Confluent Platform 7.3 is below this floor, you must upgrade Confluent Platform before raising CFK. While you are still on CFK 3.1, keep the Confluent Platform upgrade within its own supported range of Confluent Platform 7.3 to 8.1, not the CFK 3.3 range. - CFK-managed KRaft migration requires at least Confluent Platform 7.6, though 7.7 or later is recommended for production. As a result, the Confluent Platform upgrade in [Step 1](#co-upgrade-example-step1) must reach at least Confluent Platform 7.6. - Because the cluster runs in ZooKeeper mode, you must complete the KRaft migration in [Step 3](#co-upgrade-example-step3) before upgrading to Confluent Platform 8.x in [Step 5](#co-upgrade-example-step5). - The cluster uses classic Control Center (Legacy), so plan the Control Center migration before the final Confluent Platform upgrade. **The path** Open the [support matrix](co-plan.md#co-operator-supported-versions) in a separate tab to follow along. ![Multi-version upgrade path from |co| 3.1 + |cp| 7.3 (|zk|) to |co| 3.3 + |cp| 8.3 (|kraft|)](images/co-upgrade-multi-version-example.svg) **Walkthrough** 1. Upgrade Confluent Platform while staying on CFK 3.1: Upgrade Confluent Platform from 7.3 to 7.7 (or later, up to 8.1). CFK 3.1 supports Confluent Platform 7.3 through 8.1, so this stays inside your current CFK’s range. While the bare minimum target for this jump is Confluent Platform 7.5, upgrading to 7.7 satisfies the Confluent Platform 7.6 or later requirement for production KRaft migration in [Step 3](#co-upgrade-example-step3). For details, see [Upgrade Confluent Platform Using Confluent for Kubernetes](co-upgrade-cp.md#co-upgrade-cp). 2. Upgrade CFK to 3.3: With Confluent Platform at 7.7, CFK 3.3 supports both your current Confluent Platform and the target Confluent Platform 8.3. As a result, this single CFK upgrade covers the rest of the upgrade path. For details, see [Upgrade Confluent for Kubernetes](co-upgrade-cfk.md#co-upgrading). 3. Migrate ZooKeeper to KRaft: Confluent Platform 8.x removes support for ZooKeeper, making this migration mandatory before you upgrade to Confluent Platform 8.x. CFK supports KRaft migration starting at Confluent Platform 7.6, which is why [Step 1](#co-upgrade-example-step1) upgraded your environment to Confluent Platform 7.7. For details, see [Migrate a Single Cluster from ZooKeeper to KRaft](co-migrate-kraft-procedure.md#co-migrate-kraft). 4. Migrate to Control Center: If you use Control Center (Legacy), migrate your alerts and switch to Control Center before upgrading to Confluent Platform 8.x. Confluent Platform 8.x does not support Control Center (Legacy). For details, see [Migrate Control Center (Legacy) to Control Center](co-upgrade-c3.md#co-upgrade-c3). Skip this step if you do not use Control Center (Legacy). 5. Upgrade Confluent Platform to 8.3: With CFK 3.3, a KRaft-based cluster, and (if applicable) Control Center in place, upgrade Confluent Platform to the target version. For details, see [Upgrade Confluent Platform Using Confluent for Kubernetes](co-upgrade-cp.md#co-upgrade-cp). ## Next steps - For pre-upgrade tasks and known issues, see [Pre-upgrade tasks and known issues](co-upgrade-considerations.md#co-upgrade-additional-considerations). - To upgrade the CFK Operator, see [Upgrade Confluent for Kubernetes](co-upgrade-cfk.md#co-upgrading). - To upgrade Confluent Platform components, see [Upgrade Confluent Platform Using Confluent for Kubernetes](co-upgrade-cp.md#co-upgrade-cp). - To migrate Confluent Control Center (Legacy) alerts to Control Center and upgrade Control Center, see [Migrate to and Upgrade Control Center](co-upgrade-c3.md#co-upgrade-c3).