> ## Documentation Index
> Fetch the complete documentation index at: https://bifrost-dev.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# v2.1.42

> Helm v2.1.42 changelog - 2026-09-14

<Update label="Bifrost Helm" description="v2.1.42">
  ## Changelog

  * Added `mcp.clientConfigs[].perUserHeaderKeys` — the header names each caller must individually supply under `authType: per_user_headers` (e.g. `["Authorization"]`).
  * Added `bifrost.plugins.otel.config.overhead_breakdown_enabled` (default `false`) and `bifrost.plugins.telemetry.config.overhead_breakdown_enabled` - exports the per-component overhead histogram `bifrost_overhead_component_microseconds`, overhead latency split by the `overhead_component` label.
  * Fixed `bifrost.plugins.otel.config.export_overhead_spans` not rendering into `config.json`.
</Update>