… this release we completely refactored the configuration internals and moved from [spf13/viper](https://github.com/spf13/viper) to [knadh/koanf](https://github.com/knadh/koanf):

1. Configuration sourcing works from all sources (file, env, cli flags) with validation against the configuration schema, greatly improving the developer experience when changing or updating configuration.
2. Configuration reloading has improved significantly and works excellently on Kubernetes.
3. Performance gains that remove the need for a cache layer between the configuration system and ORY Hydra.
4. Loading of several config files using the `--config` flag now possible.
5. Configuration values are now sent to the tracer (e.g. Jaeger) if tracing is enabled.

Please be aware that deprecated configuration flags have finally been removed with this change. It is also possible that ORY Hydra might complain about an invalid configuration due to a significantly improved validation process.

In addition, this release includes the new OpenID Connect Conformity Test Suite as part of the ORY Hydra CI pipeline. This means every PR and change will be checked for OpenID Connect Compliance. As part of these tests, we uncovered some regression issues which have since been resolved. Please be aware that fields `error_hint` and `error_debug` will no longer be sent. You can re-enable those legacy fields by setting `oauth2.include_legacy_error_fields` to `true`.

Furthermore, support for OpenID Connect flows `response_mode=form_post` was added and has been tested with the OpenID Connect Conformity Test Suite, making it ready for production.

Several other bugs have been resolved and we have completely overhauled the tests, deprecating test tables in favor of test suites. This greatly improves the readability of our tests and allows new contributors to more easily understand what is going on!

If you wish to get into ORY Hydra, check out the newly published YouTube tutorial:

[![ORY Hydra YouTube Quickstart Tutorial](https://raw.githubusercontent.com/ory/web/master/static/images/newsletter/hydra-1.9.0/YouTube-tutorial-hydra-preview.png)](https://www.youtube.com/watch?v=tlO9p2E501A)