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Mithril Release Process

· 4 min read
Mithril Team

Mithril follows a defined release process

As the Mithril project grew and more and more SPOs became involved in testing Mithril, it became obvious we need clearer identification of artifacts running on various parts of the network. Moreover, on our road towards mainnet availability we'll need to strengthen our testing process in order to validate Mithril network on more realistic environments.

Release Process

We want our release process to follow some basic principles:

  • Continuous Integration: New code is integrated into the main codeline frequently which triggers automated build and test process.
  • Continuous Deployment: New artifacts produced by the build process are continuously deployed to a suitable environment where it can be used and tested by an increasing number of parties.
  • Deployment Pipeline: The deployment process is embodied in a pipeline that describes and implements all the necessary steps to release a new version of Mithril.
  • Artifact Promotion: An artifact is built once and only once and is promoted while travelling through the build pipeline.

Here is a high-level picture of this process:

Release Process

  • We will use a custom version based on SemVer for all the crates, binaries and containers of the repository and for the GitHub release.
  • We release a new distribution every 2 weeks (this duration is subject to changes as the project matures)
    • The released version is named after the year and its week number: YYWW.patch (e.g. 2250.0).
    • In case of critical regressions happening in production, a patch version will be released in between "official" releases as a hotfix.
  • A new version YYWW.0 will have the following life cycle:
    • A commit abc123 merged on main branch is deployed on the network named testing-preview.
    • A commit def456 tagged with YYWW.0-prerelease is deployed on the network named pre-release-preview.
    • A GitHub release YYWW.0-prerelease is created and linked with the YYWW.0-prerelease tag and marked as pre-release.
    • A tag YYWW.0-prerelease is qualified and selected for release or rejected (and replaced by a YYWW.1-prerelease tag if necessary on a fed789).
    • If the tag YYWW.0-prerelease is selected, a new tag is created and name YYWW.0 on the same commit def456.
    • A GitHub release YYWW.0 is created and linked to the YYWW.0 tag and marked as release.
    • The commit def456 with tag YYWW.0 is deployed to the network named release-preprod.
  • The Cargo.toml versions of the crates are updated (if required) just before creating the YYWW.0-prerelease tag .
  • The documentation website is also updated at the same time where the next version becomes the current version, leaving future updates be appended to the next version during the upcoming developments.
  • In order to simplify the life of Mithril users, we have introduced a version of the Mithril API used between client/signer and aggregators to check if the nodes are able to communicate together (following semver and considering the versions are compatible only if they share the same minor).
  • Our main distribution artefact is currently docker (OCI) images. We also provide more packages, eg. .deb packages or compiled binaries (some of them available on multiple platforms, e.g. Windows or macOS) to simplify users' life.
  • We also publish some of our crates on the registry whenever a new version is created (e.g. mithril-stm).


  • We maintain different Mithril networks (eg. servers, VMs, configurations...) to which artifacts are deployed at various stages of the process:
    • testing-preview: This is an internal environment based on the preview cardano testnet where most of the automated tests happen. It is also used to test features as soon as they are merged on the main branch.
    • pre-release-preview: This is a persistent environment based on the preview cardano testnet. SPOs which are active on preview are welcomed to take part in the Mithril signing process and to test new pre-release distributions deployed there.
    • release-preprod: Another persistent environment, based on the preprod cardano testnet, where more SPOs are expected to join and test, updated less frequently (on actual release distributions).
    • (LATER) mainnet: Production environment where new releases are deployed once qualifed on release-preprod.

Further Reading