Ubuntu 20.04 (Focal Fossa) is approaching the end of its supported lifecycle on Semaphore. To ensure the security, reliability, and maintainability of our platform, we are announcing the deprecation and end of life of Ubuntu 20.04 build environments.
Semaphore users should consider switching to Ubuntu 24.04 as Ubuntu 22.04 is scheduled for deprecation during Q2 of 2026.
Why We’re Deprecating Ubuntu 20.04
As operating systems age, they cease to receive timely security updates and ecosystem support. Continuing to run CI workloads on deprecated operating systems increases operational risk and limits our ability to ship improvements.
Deprecation Timeline
We will gradually phase out Ubuntu 20.04 using a series of brownout periods. During these windows, jobs configured to run on Ubuntu 20.04 will temporarily fail to start. This is intentional and designed to help you detect remaining usage before final removal.
First Brownout Period
February 2 – 8, 2026
Jobs running on Ubuntu 20.04 will not start for 15 minutes during the following times:
- UTC 00:00 — 00:15
- UTC 10:00 — 10:15
- UTC 15:00 — 15:15
Second Brownout Period
February 9 – 15, 2026
Jobs running on Ubuntu 20.04 will not start for 30 minutes during the following times:
- UTC 00:00 — 00:30
- UTC 10:00 — 10:30
- UTC 15:00 — 15:30
Third Brownout Period
February 16 – 22, 2026
Jobs running on Ubuntu 20.04 will not start for 1 hour during the following times:
- UTC 00:00 — 01:00
- UTC 10:00 — 11:00
- UTC 15:00 — 16:00
Fourth Brownout Period
February 23 – 29, 2026
Jobs running on Ubuntu 20.04 will not start for 3 hours during the following times:
- UTC 00:00 — 03:00
- UTC 10:00 — 13:00
- UTC 15:00 — 18:00
End of Life
Starting March 2026, Ubuntu 20.04 build environments will reach end of life on Semaphore.
At this point:
- Jobs configured to run on Ubuntu 20.04 will no longer start
- The Ubuntu 20.04 image will be fully removed from the platform
What You Need to Do
To avoid any disruption, update your pipelines to use a supported Ubuntu version as soon as possible.
- Identify Usage: check your Semaphore configuration files for references to Ubuntu 20.04 (for example, `ubuntu2004`).
- Migrate to a Supported Ubuntu Version: we recommend migrating to Ubuntu 24.04] if possible to ensure you are using the latest version available. If you cannot use Ubuntu 24.04, you can switch to Ubuntu 22.04. But keep in mind that this image is scheduled for deprecation during Q2 of 2026.
- Validate Your Pipelines: run your pipelines after upgrading to ensure all dependencies and scripts work correctly on the new environment.
Need Help?
If you have questions or run into issues while migrating, please reach out to Semaphore support or consult our documentation. We strongly encourage completing your migration before the first brownout period begins in February 2026.
Thank you for helping us keep Semaphore secure, stable, and up to date.
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