We want to inform you about an upcoming change concerning our Ubuntu 18.04 image. To keep up with evolving technology standards, we’ll be phasing out the Ubuntu 18.04 image as of 31 March 2024, following the end of its standard support on 31 May 2023.
To ease into this transition and minimize disruption we’ve scheduled a series of brownouts beginning eight weeks prior to the service end date.
Ubuntu 18.04 Deprecation Timeline
Brownouts will take place in the period between February 5th 2024 – March 31st 2024.
During the brownouts any jobs that use Ubuntu 18.04 will not start until the brownout is over. They will occur at the following times during each day:
- UTC 00:00
- UTC 10:00
- UTC 15:00
For the exact schedule, please check our detailed timeline:
Date | What will happen |
February 5 – 18, 2024 | First Brownout Period Semaphore will not start jobs that run on Ubuntu 18.04 machines for 15 minutes at a time for the given periods: UTC 00:00 β 00:15 UTC 10:00 β 10:15 UTC 15:00 β 15:15Β |
February 19 – March 3, 2024 | Second Brownout Period Semaphore will not start jobs that run on Ubuntu 18.04 machines for 30 minutes at a time for the given periods: UTC 00:00 β 00:30 UTC 10:00 β 10:30 UTC 15:00 β 15:30Β |
March 4 – 17, 2024 | Third Brownout Period Semaphore will not start jobs that run on Ubuntu 18.04 machines for 1 hour at a time for the given periods: UTC 00:00 β 01:00 UTC 10:00 β 11:00 UTC 15:00 β 16:00Β |
March 18 – 31, 2024 | Fourth Brownout Period Semaphore will not start jobs that run on Ubuntu 18.04 machines for 3 hours at a time for the given periods: UTC 00:00 β 03:00 UTC 10:00 β 13:00 UTC 15:00 β 18:00Β |
Starting April 2024 | Ubuntu 18.04 Jobs End of Life The jobs that run on Ubuntu 18.04 will not start and the image will reach EOL. |
Why is Ubuntu 18.04 being deprecated?
Semaphore is committed to providing you and your team with the most stable and secure experience possible.
Ubuntu 18.04 has reached End of Life (EOL) in May 31, 2023 and stopped receiving hardware and maintenance updates.

Ubuntu 20.04 enhances your development with faster performance due to improved resource usage and an updated kernel. Offering support until April 2025, it ensures longevity and security with a continuously updated software stack.
For more on Ubuntu 20.04 benefits, please read our migration documentation.
Does the Ubuntu 18.04 image deprecation affect me?
If any of your projects currently use Ubuntu 18.04 to run jobs, plan to migrate from the deprecated images as soon as possible.
To check if your workflow uses the Ubuntu 18.04 image, inspect the os_image:
line in your YAML file:

Or you can check the image in the Agent section of your job in the Workflow Builder:

How to Migrate
Before migrating, please check your software version requirements in the software availability metrics located in our migration documentation.
If the available software stack matches your requirements, changing the image type is as simple as changing theΒ os_image:
Β line to use ubuntu2004
Β instead of ubuntu1804
Β in your semaphore.yml
file:

You can also update it in the Workflow Builder:

Conclusion
Feel free to reach out to us atΒ support@stg-semaphoreci-dev.kinsta.cloudΒ if you have any questions or need our assistance. Weβll be happy to help.
Happy building!