Container Engine for Kubernetes now supports Kubernetes version 1.23.4, in addition to versions 1.22.5 and 1.21.5. Oracle recommends you upgrade your Kubernetes environment to version 1.23.4. For more information about Kubernetes 1.23.4, see the Kubernetes Changelog.

Note the following:

• With the availability of support for Kubernetes version 1.23.4, Container Engine for Kubernetes will cease support for Kubernetes versions 1.20.11 on July 19, 2022. As a result, you will no longer be able to:
  • Create new clusters running Kubernetes versions 1.20.11.
  • Add new node pools to existing clusters running Kubernetes versions 1.20.11.
• If you currently have existing clusters running Kubernetes version 1.20.11, Oracle strongly recommends you immediately upgrade those clusters to Kubernetes versions 1.23.4, 1.22.5, or 1.21.5. You can upgrade control plane nodes through unsupported minor versions. Kubernetes requires that you upgrade control plane nodes one minor version at a time. So if a control plane node is running Kubernetes version 1.19.15 (an unsupported minor version), you must upgrade it to Kubernetes version 1.20.11 (also an unsupported minor version), before upgrading it to 1.21.5.

To upgrade a cluster to a new Kubernetes minor version:

1. Upgrade the Kubernetes version running on the control plane by following the instructions in Upgrading the Kubernetes Version on Control Plane Nodes in a Cluster.
2. Having upgraded the control plane, upgrade the Kubernetes version running on worker nodes in a node pool by following the instructions Upgrading the Kubernetes Version on Worker Nodes in a Cluster.

Note:

Always follow the Kubernetes skew policy for Kubernetes minor version support.

Example skew policy:

• Kubernetes control plane nodes are at version 1.23.4
• Kubernetes worker nodes must be at version 1.23.4, 1.22.5, or 1.21.5

Note that although the worker nodes in a node pool must follow the Kubernetes skew policy, you do not have to upgrade them one minor version at a time.

For more information, see Upgrading Clusters to Newer Kubernetes Versions.