# istio_zipkin-trace-context-option.yaml
apiVersion: release-notes/v2
kind: feature
area: telemetry

# issue is a list of GitHub issues resolved in this note.
issue: []

docs:
  - '[envoy] https://www.envoyproxy.io/docs/envoy/latest/api-v3/config/trace/v3/zipkin.proto#envoy-v3-api-enum-config-trace-v3-zipkinconfig-tracecontextoption'
  - '[reference] https://istio.io/latest/docs/reference/config/istio.mesh.v1alpha1/'
  - '[usage] https://istio.io/latest/docs/tasks/observability/distributed-tracing/'

releaseNotes:
- |
  **Added** support for Zipkin TraceContextOption configuration to enable dual B3/W3C header propagation.
  Configure with `trace_context_option: USE_B3_WITH_W3C_PROPAGATION` in MeshConfig extensionProviders to
  extract B3 headers preferentially, fall back to W3C traceparent headers, and inject both header types
  upstream for better tracing interoperability.