Update RTD Build

[saulshanabrook]

From an email:

Hello!

We are announcing the deprecation of the Ubuntu 20.04 LTS build image (build.os: ubuntu-20.04) on Read the Docs. After June 1, 2026, projects still using this image will fail when building until they are updated to a supported Ubuntu image.This change keeps our build images current and helps us prepare for Ubuntu 26.04 LTS support. Ubuntu 20.04 LTS is now an older base image and is no longer receiving security updates, so we consider it insecure to continue to offer.What do I need to do?Update your .readthedocs.yaml to use a newer supported image. For most projects, we recommend:build: os: ubuntu-24.04 Read the Docs currently supports ubuntu-22.04, ubuntu-24.04, and ubuntu-lts-latest for build.os. See all options in the docs: https://docs.readthedocs.io/en/stable/config-file/v2.html#build-osIf your project depends on system packages or tool versions that differ on newer Ubuntu releases, please test your builds early and update before June 1, 2026.Deprecation timelineMarch 30, 2026: Publish deprecation announcement.Before June 1, 2026: Email maintainers of active projects still using ubuntu-20.04.June 1, 2026: Remove the ubuntu-20.04 build image.Are my projects affected?We found the following projects where you are a maintainer that may be impacted by this change:egglog-pythonpython-code-dataRead the full announcement: https://about.readthedocs.com/blog/2026/03/ubuntu-20-04-deprecated/Contact us or reply to this email if you have any questions about this change.
Keep documenting,Read the Docs

Hello!
We are announcing the deprecation of the Ubuntu 20.04 LTS build image (build.os: ubuntu-20.04) on Read the Docs. After June 1, 2026, projects still using this image will fail when building until they are updated to a supported Ubuntu image.

This change keeps our build images current and helps us prepare for Ubuntu 26.04 LTS support. Ubuntu 20.04 LTS is now an older base image and is no longer receiving security updates, so we consider it insecure to continue to offer.

What do I need to do?
Update your .readthedocs.yaml to use a newer supported image. For most projects, we recommend:

build:
os: ubuntu-24.04
Read the Docs currently supports ubuntu-22.04, ubuntu-24.04, and ubuntu-lts-latest for build.os. See all options in the docs: https://docs.readthedocs.io/en/stable/config-file/v2.html#build-os

If your project depends on system packages or tool versions that differ on newer Ubuntu releases, please test your builds early and update before June 1, 2026.

Deprecation timeline
March 30, 2026: Publish deprecation announcement.
Before June 1, 2026: Email maintainers of active projects still using ubuntu-20.04.
June 1, 2026: Remove the ubuntu-20.04 build image.
Are my projects affected?
We found the following projects where you are a maintainer that may be impacted by this change:

egglog-python

python-code-data

Read the full announcement: https://about.readthedocs.com/blog/2026/03/ubuntu-20-04-deprecated/

Contact us or reply to this email if you have any questions about this change.

Keep documenting,
Read the Docs