{#if release.hasArmImages}

<Callout type="warning" title="ARM servers are temporarily not supported">

ARM-based servers are temporarily not supported. Due to significant declines in the availability and reliability of this server architecture, we can no longer recommend it. This is a temporary measure, and we will restore support once the situation improves.

If your cluster uses ARM-based nodes, you must migrate them to x86 nodes before updating:

- **Updates are blocked.** Without available ARM server capacity, nodes cannot be reliably provisioned, which prevents updates from completing.
- **No automatic replacement on failure.** If an ARM server fails, there is currently no way to obtain an automatic replacement.

See [Migrate ARM servers to x86 in your cluster](/docs/hetzner/apalla/servers-and-nodes/provision/migrate-arm-to-x86) for instructions.

</Callout>

{/if}

{#if release === stack.latest}

## You are up to date! 🎉

If you wish to upgrade from an old ClusterStack version, please go to the version selector on top of the navigation and select your current version.

{:else if release === minor.latest}

## You are on the latest ClusterStackRelease! 🎉

Right now you are on the latest ClusterStackRelease available for Kubernetes <code>1.35</code>.

If you wish to upgrade from an old ClusterStackRelease version, please go to the version selector on top of the navigation and select your version.

If you want to upgrade the Kubernetes version instead, visit the [Updating the cluster to a new Kubernetes version](/docs/hetzner/apalla/clusters/upgrades/upgrade-to-a-new-kubernetes-version) guide.

{:else}

## Introduction to ClusterStack Releases

Syself is releasing a new version of the ClusterStacks every two to three weeks. These releases may contain minor updates, such as a Kubernetes patch version, or the version of some cluster components or node images.

This guide will detail the process of updating from to <code>v4</code>.

## Preparing the clusterstack object

Check if `autoSubscribe` is set to `true` or `false` in your clusterstack object and follow the steps for your case:

> [!NOTE]
> The `autoSubscribe` key in the clusterstack object indicates that Syself Autopilot will automatically fetch the latest ClusterStackRelease version and make it available for use.

<Tabs id="autosubscribe" items={['autosubscribe: true', 'autosubscribe: false']}>

<TabItem value="autosubscribe: true">

{#if upgrade.toMinorLatest.length === 1}

The latest version is automatically available for you. You don't need to do anything. Keep reading the next steps.

{:else}

The latest version is automatically available for you, but you still need to specify the versions in between.

For that, add [] to the `spec.versions` array in your ClusterStack:

```yaml vars persistBlur title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: true
  versions: []
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
```

{/if}

</TabItem>

<TabItem value="autosubscribe: false">

{#if upgrade.toMinorLatest.length === 1}

You can go to the latest version directly. To make it available, add <code>v4</code> to the versions array in your ClusterStack object:

```yaml vars persistBlur title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: false
  versions: ["v4"]
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
```

{:else}

You need to specify the ClusterStackRelease versions in between using the `spec.versions` array in your ClusterStack object.

The following is the complete (and shortest) tested upgrade path to go from your current version to <code>hetzner-apalla-1-35-v4</code>:

```yaml vars persistBlur title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: false
  versions: []
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
```

{/if}

</TabItem>

</Tabs>

## Checking the available ClusterStackReleases

Check if the `ClusterStackReleases` you need are available with:

{#if upgrade.toMinorLatest.length === 1}

```console vars
$ kubectl get clusterstackrelease
NAME                     K8S VERSION   READY   AGE   REASON   MESSAGE
hetzner-apalla-1-35-v4   v1.35.7       true    2d
hetzner-apalla-1-35-v4   v1.35.7       true    1m
```

{:else}

```console vars
$ kubectl get clusterstackrelease
NAME                     K8S VERSION   READY   AGE   REASON   MESSAGE
hetzner-apalla-1-35-v4   v1.35.7       true    2d
...                      ...           true    1m
hetzner-apalla-1-35-v4   v1.35.7       true    1m
```

{/if}

Note down the values of the `NAME` and `K8S VERSION` columns from the release you want to upgrade to. In this case, <code>hetzner-apalla-1-35-v4</code> and <code>v1.35.7</code>.

## Upgrading the cluster object

Edit your cluster and change the `spec.topology.class` and `spec.topology.version` to match the `NAME` and `K8S VERSION` of the ClusterStackRelease, respectively.

This can be achieved either by editing the resource inside the management cluster, or by updating it in your GitOps repository.

{#if upgrade.toMinorLatest[0]?.kubernetes === minor.latest.kubernetes}

In this case, you only need to update one version.

> [!NOTE]
> The cluster manifest below uses `cluster.x-k8s.io/v1beta2`, the current default API version for CAPI core resources. See [Cluster API v1beta2](/docs/hetzner/apalla/clusters/upgrades/migrate-a-manifest-to-v1beta2) for more information.

```yaml vars persistBlur title="cluster.yaml"
apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
metadata:
  name: mycluster
spec:
  topology:
    classRef:
      name: {upgrade.toMinorLatest[0]?.name}
    version: {upgrade.toMinorLatest[0]?.kubernetes}
    controlPlane:
      replicas: 3
    workers:
      machineDeployments:
        - class: workeramd64hcloud
          name: md-0
          replicas: 1
          failureDomain: nbg1
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cpx42
    variables:
      - name: region
        value: nbg1
      - name: controlPlaneMachineTypeHcloud
        value: cpx42
```

{:else}

<Timeline />

{/if}

Now, your cluster will be updated (with no downtime!) to the cluster stack version you specified.

If you need to update to another version, wait for the current update process to finish. You can check if it's done by checking the nodes in your cluster:

```console
$ kubectl get nodes
```

If you still have old nodes, this means the update is in progress. In this case, wait until the output shows only new nodes.

{/if}