I'm sorry, but the knowledge sources provided do not contain a comprehensive or explicit list of breaking changes for self-service Ory Hydra between versions 2.1.0 and 2.3.0. However, the upgrade guides and documentation strongly recommend reviewing the [Ory Hydra changelog](https://github.com/ory/hydra/blob/master/CHANGELOG.md) and release notes before upgrading, as these documents detail breaking changes, new features, and migration steps for each release. The upgrade process also emphasizes the importance of reading these resources to identify any changes that may impact your deployment, especially for major version upgrades or when moving between significant minor versions like 2.1.0 to 2.3.0. If you are planning an upgrade, please consult the changelog directly for the most accurate and up-to-date information on breaking changes relevant to your versions of interest [Docs: Apply upgrades](https://www.ory.sh/docs/hydra/self-hosted/upgrade). If you need more specific details, please refer to the official changelog or release notes for each version increment between 2.1.0 and 2.3.0.

To migrate Ory Hydra from v2.1.0 to v2.3.0, follow these general steps as outlined in the official Ory documentation: 1. Read the Release Notes and Changelog Before upgrading, carefully review the [release notes](https://github.com/ory/hydra/releases) and the [CHANGELOG.md](https://github.com/ory/hydra/blob/master/CHANGELOG.md) for all versions between v2.1.0 and v2.3.0. This will help you identify any breaking changes or important updates that may affect your deployment. The documentation emphasizes this as a critical step for a successful upgrade. 2. Backup Your Data Always create a backup of your database and configuration files before starting the upgrade process. This is crucial to ensure you can restore your system in case of any issues during the migration. 3. Update the Ory Hydra SDK If your application uses the Ory Hydra SDK, update it to a version compatible with v2.3.0. 4. Install the New Version Download and install Ory Hydra v2.3.0. You can find installation instructions in the [Install Ory Hydra guide](https://www.ory.sh/docs/hydra/self-hosted/deploy-hydra-example#install-ory-hydra). 5. Run Database Migrations Execute the following command to apply any necessary database schema changes:

hydra migrate sql

This command updates your database schema to be compatible with the new version. If you are using Docker, you can run:

docker run \      -e DSN=your_database_connection_string \      oryd/hydra:v2.3.0 \      migrate sql -e -f /path/to/config.yaml

Replace

your_database_connection_string

and

/path/to/config.yaml

with your actual values. 6. Start the New Version Once migrations are complete, start Ory Hydra v2.3.0 using your existing configuration. 7. Test Your Setup Verify that your system is functioning as expected after the upgrade. Note: The documentation does not provide a version-specific migration guide for v2.1.0 to v2.3.0, nor does it list breaking changes for these versions. You must consult the [changelog](https://github.com/ory/hydra/blob/master/CHANGELOG.md) for details on what may affect your deployment during this upgrade window. If you encounter issues, consider a stepped upgrade (e.g., v2.1.0 → v2.2.x → v2.3.0) and consult the Ory community for support [Docs: Apply upgrades](https://www.ory.sh/docs/hydra/self-hosted/upgrade). If you need more detailed, version-specific instructions, please refer directly to the changelog and release notes as recommended by the official documentation.