# istio_add-customized-ca-metadata-support-to-istio-agent.yaml
apiVersion: release-notes/v2
kind: feature
area: traffic-management
issue:
- 55064
releaseNotes:
- |
  **Added** an environment variable prefix `CA_HEADER_` (similar to `XDS_HEADER_``) that can be added to CA requests for different purposes, such as routing to appropriate external Istiods. Istio sidecar proxy, router, and waypoint now support this feature.