Container Service for Kubernetes (ACK) provides container-centric solutions based on open source Kubernetes. As new Kubernetes versions are released, the list of Kubernetes versions supported by ACK also changes. New Kubernetes versions are added to the list and outdated Kubernetes versions are discontinued. This topic describes how ACK supports different Kubernetes versions, including the release cycle, support policies, and risks of using outdated Kubernetes versions.
Release notes
The following table describes the Kubernetes versions that are supported by ACK clusters and ACK Serverless clusters.
Version | Status | Release date (ACK) | Discontinue date (ACK) |
Released | September 2024 | September 2025 | |
Released | June 2024 | June 2026 | |
Released | October 2023 | October 2025 | |
Released | April 2023 | April 2025 |
Release cycle
After the Kubernetes community releases a new minor version, ACK performs a risk assessment and consistency test on the version. You can create clusters of the new version and upgrade existing clusters to the new version after the new Kubernetes version passes the tests. In most cases, the preparations take two weeks and the duration varies based on the differences between versions.
After the Kubernetes community releases a new patch version for a minor version, ACK determines whether to release the patch version based on the risk level of the issue fixed by the patch version. In most cases, ACK requires about 24 hours to perform a risk assessment and consistency test on a patch version that fixes critical issues, such as high-risk security vulnerabilities. Then, ACK allows you to create clusters of the new version and upgrade existing clusters to the new version.
Version description
The Kubernetes versions supported by ACK follow the semantic versioning scheme in the x.y.z-aliyun.n format. x.y.z is the open source Kubernetes version. x is the major version, y is the minor version, z is the patch version, and n is the ACK patch version. For example, version 1.31.1-aliyun.1 is based on open source Kubernetes 1.31.1. For more information about Kubernetes versions, see Kubernetes Release Versioning.
Rules for supporting Kubernetes versions
Cluster creation
ACK allows you to create clusters of the latest three minor versions. For example, the latest minor versions are Kubernetes 1.28, 1.30, and 1.31. When ACK starts to support Kubernetes 1.31, Kubernetes 1.26 is discontinued and you can no longer create clusters of Kubernetes 1.26. In addition, the outdated patch version is no longer available.
Cluster upgrade
ACK allows you to upgrade ACK clusters from a minor version to the following minor version. You cannot skip minor versions when you upgrade ACK clusters or roll back your ACK clusters to an earlier version. For example, if your cluster runs Kubernetes 1.28 and you want to upgrade the cluster to Kubernetes 1.31, you need to first upgrade the cluster to Kubernetes 1.30 and then to Kubernetes 1.31.
ACK allows you to upgrade an ACK cluster only to the latest patch version. You cannot upgrade your cluster to outdated patch versions.
Technical support
Alibaba Cloud provides technical support for the latest three minor versions. Technical support provided by Alibaba Cloud includes consultation, online tutorials, and troubleshooting.
Risks of outdated Kubernetes versions
After the cluster version expires, you cannot use the latest features released by the Kubernetes community and ACK, and you may face the following risks:
You cannot obtain feature patches.
You cannot obtain security patches.
You can obtain only limited technical support.
ACK does not guarantee that technical support can be provided at the first time except for issues related to cluster and component upgrades.
In addition, for availability and security purposes, ACK reserves the right to force the clusters that run outdated Kubernetes versions to upgrade.
ACK will send notifications to you by text messages, emails, and internal messages at least one month before the upgrade. Pay attention to the notifications and prepare for the upgrade in advance.
References
We recommend that you learn the updates and usage notes of each Kubernetes version before you upgrade your cluster. For more information about cluster updates, see Manually update ACK clusters.