Deprecated MetalLB managed annotations not removed from service on upgrade #2642

MetalLB Version

0.14.9

Deployment method

Charts

Main CNI

flannel

Kubernetes Version

1.31.4

Cluster Distribution

k3s

Describe the bug

Annotations starting with "metallb.universe.tf" are deprecated as announced.

However, if a service was deployed using an older version, it contains metallb managed annotation metallb.universe.tf/ip-allocated-from-pool.

To Reproduce

1. Deploy a service with metallb < 0.14.9 and assign an IP using metallb.universe.tf/loadBalancerIPs
2. Upgrade metallb to 0.14.9
3. Re-apply the same service after changing the deprecated annotation to metallb.io/loadBalancerIPs

Expected Behavior

MetalLB will complain about use of deprecated annotations in kubernetes events - however that annotation was set by MetalLB.

Do note that service gets the new annotation metallb.io/ip-allocated-from-pool, but it does not remove the old annotation - which is what I'd expect.

Additional Context

# Source: haproxy/templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: haproxy
  namespace: default
  labels:
    helm.sh/chart: haproxy-1.23.0
    app.kubernetes.io/name: haproxy
    app.kubernetes.io/instance: haproxy
    app.kubernetes.io/version: "3.0.4"
    app.kubernetes.io/managed-by: Helm
  annotations:
    metallb.io/loadBalancerIPs: "192.168.0.50"
spec:
  type: LoadBalancer
  selector:
    app.kubernetes.io/name: haproxy
    app.kubernetes.io/instance: haproxy
  externalTrafficPolicy: Local
  ports:
  - name: http
    protocol: TCP
    port: 80
    targetPort: http
  - name: https
    protocol: TCP
    port: 443
    targetPort: https

I've read and agree with the following

• I've checked all open and closed issues and my request is not there.
• I've checked all open and closed pull requests and my request is not there.

I've read and agree with the following

• I've checked all open and closed issues and my issue is not there.
• This bug is reproducible when deploying MetalLB from the main branch
• I have read the troubleshooting guide and I am still not able to make it work
• I checked the logs and MetalLB is not discarding the configuration as not valid
• I enabled the debug logs, collected the information required from the cluster using the collect script and will attach them to the issue
• I will provide the definition of my service and the related endpoint slices and attach them to this issue