A KKP minor version supports all Kubernetes versions which were supported upstream at the time of its release. You can find more details about the upstream support policy in the Version Skew Policy.
As time passes, patch versions of KKP will support new patch versions of Kubernetes that have been released since, as well as drop old patch versions if they are affected by critical bugs.
KKP will typically drop support of minor versions of Kubernetes which have gone EOL, even during the lifecycle of a KKP minor version (e.g. from 2.16.1 to 2.16.2). This of course results in any minor version of KKP being eventually limited to two and later one minor version of Kubernetes.
One notable exception is when upgrading from an older version of Kubernetes might require extensive migration of loads running within the updated clusters (e.g. API version deprecations) – in these cases KKP will maintain LIMITED support of an EOL Kubernetes version(s) for an additional release cycle for the purpose of facilitating these migrations.
In the following table you can find the supported Kubernetes versions for the current KKP version.
| KKP version | 1.26 | 1.25 | 1.24 | 1.231 | 1.221 | 1.211 | 1.201 | 1.191 |
|---|---|---|---|---|---|---|---|---|
| 2.22.x | ✓ | ✓ | ✓ | - | - | - | - | - |
| 2.21.x | - | - | ✓ | ✓ | ✓ | - | - | - |
| 2.20.x | - | - | - | ✓ | ✓ | ✓ | ✓ | - |
Upgrades from a previous Kubernetes version are generally supported whenever a version is marked as supported, for example KKP 2.19 supports updating clusters from Kubernetes 1.20 to 1.21.
KKP has some incompatibilities with cloud providers, e.g. because their in-tree cloud provider implementation has been removed from upstream Kubernetes. For KKP 2.22.x, the following incompatibilities apply:
| Condition | Incompatible with Kubernetes | Notes |
|---|---|---|
| vSphere + in-tree cloud provider | >= 1.25 | Must be migrated to external CCM first. |
| OpenStack + in-tree cloud provider | >= 1.26 | Must be migrated to external CCM first. |