Kubernetes 1.37 enforces storage version migration GA

Kubernetes 1.37 makes the storage version migration GA. The controller-manager now enforces a single API version per resource type and refuses writes to older schemas. The migration tool has been available for months — this is the point where the cluster starts policing the change.

It's not a migration for the data; that happened when objects were written in the new version. It's a migration for the API surface: the cluster stops accepting the old wire format. Any client that still sends an older version gets an error instead of a silent conversion.

The migration took this long because it breaks the backwards-compatibility guarantee that Kubernetes has relied on since 1.0. By making it GA, the project is saying the old API versions have been deprecated long enough and it's time to stop accepting them.

Why this matters for us: if you run a cluster, this is one of those release notes you actually need to read — the controller-manager will start rejecting old API calls and the migration tool needs to finish the job before 1.37 ships.