[Bug] Unknown field "upgradePolicy" in ClusterConfig YAML (v0.215.0) despite docs

[kobolt-log]

What were you trying to accomplish?

I was trying to create an EKS cluster using a ClusterConfig YAML file that includes the upgradePolicy field set to STANDARD to configure the Kubernetes version support type during cluster creation. This follows the official EKSCTL documentation on upgrade policies, which shows upgradePolicy as a top-level field in the YAML to enable the standard 14-month support without extended costs.

※URL referenced
https://github.com/eksctl-io/eksctl/blob/main/userdocs/src/usage/upgrade-policy.md

What happened?

The command failed immediately during YAML config loading with a JSON unmarshaling error, indicating that the upgradePolicy field is unknown. This prevents cluster creation despite the field being documented as supported in apiVersion: eksctl.io/v1alpha5. I expected the cluster to be created with the specified policy.

How to reproduce it?

1. Install EKSCTL v0.215.0 (downloaded Unix binary) on Amazon Linux 2023.
2. Create a YAML file with the following content (sensitive cluster name redacted)

apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig
metadata:
  name: ****
  region: ap-northeast-1
  version: "1.34"

upgradePolicy:
  supportType: "STANDARD"

---omission---

3. Run Command

eksctl create cluster --config-file=xxx.yaml

Logs

$ eksctl create cluster --config-file=xxx.yaml
Error: loading config file "xxx.yaml": error unmarshaling JSON: while decoding JSON: json: unknown field "upgradePolicy"

Anything else we need to know?
OS: Amazon Linux 2023 (running on EC2 instance).
EKSCTL installation: Downloaded pre-built binary for Unix from GitHub releases (not compiled from source).
Versions

$ eksctl info
eksctl version: 0.215.0
kubectl version: v1.34.1
OS: linux

[NicholasBlaskey]

Hello,

We just merged the change for this but haven't cut a release yet #8544

It looks like our documentation update went out before the release was made.

I'm going to plan to cut a release in the next few days to allow you to use the feature.