Traefik Mesh CRD schema changes and controller downgrade compatibility

Traefik Mesh stores service mesh routing, traffic splitting, and policy configuration in Kubernetes Custom Resource Definitions, so a schema change between controller versions can affect whether existing custom resources remain valid after a downgrade. The goal is to determine whether upgrading the Traefik Mesh controller and later rolling back leaves previously created or modified custom resources readable by the older controller, or whether they are rejected due to removed or retyped fields.

Kubernetes supports CRD evolution through multiple spec.versions, storage version selection, and conversion webhooks, but schema changes that alter field types or remove fields still create downgrade risk. Whether Traefik Mesh implements a conversion webhook or in-place migration to preserve custom resource readability across a controller downgrade after a schema change remains unclear and may require verification against specific release notes and installed CRD manifests.

Does a Traefik Mesh controller downgrade after a CRD schema change leave existing custom resources in an unreadable state, or are they migrated in place to remain compatible with the previous schema version? Is there a documented conversion webhook or migration mechanism in Traefik Mesh that preserves custom resource readability across controller version changes? Which Traefik Mesh release boundaries should be treated as non-reversible for custom resource schema changes?