> For the complete documentation index, see [llms.txt](https://docs.facephi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.facephi.com/docs.facephi-en/sdks/backend-sdk/backend1n/release_notes/4.2.0_release_notes.md).

# 4.2.0

This Version updates the biometric engine and introduces several quality and reliability improvements: a unit testing framework, proper Error handling for malformed inputs, configuration precedence via environment variables, and an updated Docker base image.

### Added

* Configuration precedence via environment variables using the prefix `FACEPHI_BACKEND1N_REST_*`. Environment variables now have the highest priority in the configuration chain.

### Changed

* Biometric engine update.

### Fixed

* Malformed Base64 and JSON inputs in the endpoints `/extract` and `/search` now return HTTP 400 (Bad Request) instead of HTTP 500 (Internal Server Error).
* Updated Docker base image from Ubuntu 24.04 to Ubuntu 26.04 to improve security.