Did you actually read the summary? It affects volumes for customers running 1.25 only - it is global but only for a subset of customers.
> anything that already exists will be fine and continue operating.
Any pod that already exists will be fine, but that doesn't extend to services, as they may autoscale volumes along with pods. I'm not sure many users on such an antiquated kube version would have done that, but if no one did, there would probably not be a notice.