If a customer populates the serviceEndpoints for powervs via the install config in 4.17, the validation is incorrect and persists lowercase values.

status:
  platformStatus:
    type: PowerVS
    powervs:
      serviceEndpoints:
      - name: dnsservices
        url: ...

On upgrade, the schema is currently updated to an enum, courtesy of https://github.com/openshift/api/pull/2076

The validation upgrade and ratcheting was tested, but only for the `spec` version of the field. It was assumed that spec and status validation behaved the same.

However, https://issues.redhat.com/browse/OCPBUGS-48077, has recently been found, and this means that on upgrade, all writes to the status subresource of the infrastructure object fail, until the serviceEndpoints are fixed.

In a steady state, this may not cause general cluster degredation, writing to the status of the infrastructure object is not common.

However, any controller that does attempt to write to it, will fail, and end up erroring until the value has been fixed.

There are several possible approaches to resolve this:
1. Revert https://github.com/openshift/api/pull/2076 and anything else that depended on it
2. Merge and backport the fix for https://issues.redhat.com/browse/OCPBUGS-48077
3. Introduce something in 4.18 to fix invalid values in the status (eg convert dnsservices to DNSServices)

Until one of these three (or perhaps other fixes) is taken, I think this needs to be considered a PowerVS upgrade blocker, and then management can decide if this is enough to block 4.18

    4.17 to 4.18

    1.
    2.
    3.