Astronomer Certified versioning and support

Astronomer Certified (AC) is a Debian-based, production-ready distribution of Apache Airflow that mirrors the open source project and undergoes additional levels of rigorous testing conducted by our team. New versions of AC are issued regularly based on Apache Airflow's community release schedule.

This Docker image is hosted on Astronomer's Docker registry and allows you to run Airflow on Astronomer. All projects require that you specify an AC image in your Dockerfile.

This document provides information on the following:

• How AC is versioned
• Which versions of AC are currently available
• The maintenance schedule and end-of-maintenance date for all versions

For guidelines on how to upgrade, read Upgrade Apache Airflow on Astronomer. For information about Astro Runtime's support policy, see Runtime release and lifecycle policy.

Release channels​

To meet the unique needs of different operating environments, Astronomer Certified (AC) versions are associated with the following release channels:

• Stable: Includes the latest Astronomer and Apache Airflow features, available on release
• Long-term Support (LTS): Includes additional testing, stability, and maintenance for a core set of features

All releases of AC are considered stable. The LTS release channel is a subset of the stable release channel that promises additional stability, reliability, and support from our team.

For users that want to keep up with the latest Astronomer and Airflow features on an incremental basis, we recommend upgrading to new versions of AC as soon as they are made generally available. This should be regardless of release channel. New versions of AC are issued regularly and depend on the Apache Airflow community release schedule.

If your organization prefers less frequent upgrades and functional changes, Astronomer recommends following the LTS release channel exclusively.

Versioning scheme​

Astronomer Certified follows Semantic Versioning. This means that Astronomer ships Major, Minor, and Patch releases of AC in the format of major.minor.patch-hotfix.

• Major versions are released for significant feature additions, including backward-incompatible changes to an API or DAG specification.
• Minor versions are released for functional changes, including backward-compatible changes to an API or DAG specification.
• Patch versions are released for bug and security fixes that resolve incorrect behavior.
• Hotfix versions may include bug or security fixes not yet available in community releases of Apache Airflow.

For AC 2.1.3-5, for example:

• Major = 2.
• Minor = .1
• Patch = .3
• Hotfix = -5

An AC Docker image will be published for every major and minor version of Apache Airflow. For example, AC images that correspond with Apache Airflow 2.0, 2.1, 2.2 etc. will be available on Astronomer as they're released in the open source project.

It is considered safe to upgrade to minor and patch versions within a major version. Upgrade guidance for major and LTS versions is provided with each release. There is no relation between an AC release's version number and its release channel.

Hotfix Versions​

All hotfix releases of AC have a corresponding changelog which specifies the date the hotfix was released and all individual changes made to it. Bugs that are reported by the wider Airflow community are often fixed in AC before they are fixed in the subsequent open source release.

Distribution​

AC Docker images come in two variants:

• quay.io/astronomer/ap-airflow:<version>-onbuild
• quay.io/astronomer/ap-airflow:<version>

For example, the images for Astronomer Certified 2.3.1 would be:

• quay.io/astronomer/ap-airflow:2.3.1
• quay.io/astronomer/ap-airflow:2.3.1-onbuild

For the smoothest, out-of-the-box Airflow experience, we strongly recommend and default to buster-onbuild images in your project's Dockerfile. These images incorporate Docker ONBUILD commands to copy and scaffold your Astro project directory so you can more easily pass those files to the containers running each core Airflow component.

For complex use cases that require customizing AC base image, see Customize your Airflow image on Astronomer.

Backport policy for bug and security fixes​

If a major stability bug in Astronomer Certified is identified by Astronomer, a fix is backported to all LTS versions and only the latest stable version. For users on a stable version that is not latest, Astronomer support will recommend that you upgrade. Major issues in this category may result in significant delays in task scheduling as well as potential data loss.

If a major security issue is identified, a fix will be backported and made available as a new AC hotfix version for all available stable and LTS releases. Major issues in this category are classified by a combination of impact and exploitability.

In rare instances, Astronomer support might make an exception and backport a bug or security fix to a release that is beyond the stated commitment. To submit a request for consideration, contact your customer success manager.

Astronomer Certified maintenance policy​

The maintenance period for an Astronomer Certified version depends on its release channel:

Release Channel	Maintenance Duration
Stable	6 Months
LTS	18 Months

To fix bugs, Astronomer provides patch releases as new images and recommends that organizations install them regularly to ensure optimum performance. Upgrading only when an issue occurs can delay the resolution of the issue.

For each major.minor pair, only the latest patch and hot-fix combination is supported at any given time. If you report an issue with an Astronomer Certified patch or hot-fix version that is not latest, the Astronomer Support team will always ask that you upgrade as a first step to resolution. For example, if Astronomer Certified 2.2.3 is the latest patch in the 2.2.x series, the Support team would encourage any user who reports an issue with Astronomer Certified 2.2.2 to first upgrade to 2.2.3 before starting to troubleshoot the issue.

Within the maintenance window of each Astronomer Certified version, the following is true:

• A Python wheel and set of Docker images corresponding to that version are available for download via Quay.io, PyPi and Downloads.
• Astronomer will regularly publish hotfixes for bug or security issues identified as high priority.
• The Astronomer Support team will offer support for paying customers running a supported version of AC via the Astronomer support portal.
• A user can create a new Airflow Deployment via the Software UI, CLI, or API with any supported version of AC.

When the maintenance window for a version of AC ends, the following is true:

• The Astronomer Support team is not obligated to answer questions regarding an Airflow Deployment that is running that version.
• New Airflow Deployments cannot be created with that version of AC. Unsupported versions will not render as an option in the Deployment creation process from the Software UI, API, or CLI.
• In the latest version of the Astro CLI, a warning appears when a user pushes a Docker image to Astronomer that corresponds to that version.

To ensure reliability, service is not interrupted when Astronomer Deployments are running unsupported versions of AC. You can use the Astro CLI to access unsupported AC versions for local development and testing.

End of maintenance date​

Maintenance is discontinued on the last day of the month for a given version. For example, if the maintenance window for a version of Astronomer Certified is January - June of a given year, that version is maintained by Astronomer until the last day of June.

Astronomer Certified lifecycle schedule​

The following tables list the lifecycles for each published version of Astronomer Certified. These timelines are based on the LTS and Stable release channel maintenance policies.

Stable releases​

AC Version	Release Date	End of Maintenance Date
2.3¹	April 30, 2022	March 2023
2.4	September 29, 2022	March 2023

LTS releases​

AC Version	Release Date	End of Maintenance Date
2.3¹	April 30, 2022	March 2023

¹ In November 2022, Astronomer Certified 2.3 was reclassified as an LTS release with only 12 months of support. Astronomer recommends upgrading or migrating to Astro Runtime 5.0.x to receive long term support for Apache Airflow 2.3 through October 2023. See Migrate to Astro Runtime.

If you have any questions or concerns, contact Astronomer support.