Migrate your project to .readthedocs.yaml configuration file v2

We are announcing a new requirement for all builds to use our configuration file version 2. This announcement deprecates builds without a configuration file, as well as version 1 of our configuration file.

Read the Docs will start requiring a .readthedocs.yaml configuration file for all projects in order to build documentation successfully. We will stop supporting builds without explicit configuration, because this creates implicit dependencies that users aren’t aware of. We plan to start failing builds not using configuration file version 2 on September 25, 2023.

The main reason behind this decision is that it’s hard to maintain a set of defaults that are useful for all of our users and the different tools they use to build documentation. Without a configuration file, we must guess the configuration the project needs to build, which is difficult to do reliably. Even if the defaults we chose worked well for a period of time, we found them impossible to change over time. Doing so would break projects that were relying on our defaults instead of specifying a configuration file and pinning their dependencies (e.g. OS, Python version, dependencies, etc).

Deprecation timeline

We understand this change will affect many of our users, so we have a timeline to communicate this deprecation to our users effectively.

  • June 2023: Email project owners with unsupported configurations once a week, along with an onsite notification to alert them of the deprecation.

  • Monday, July 24, 2023: Do the first brownout (temporarily enforce this deprecation) for 12 hours: 00:01 PST to 11:59 PST (noon)

  • Monday, August 14, 2023: Do a second brownout (temporarily enforce this deprecation) for 24 hours: 00:01 PST to 23:59 PST (midnight)

  • Monday, September 4, 2023: Do a third and final brownout (temporarily enforce this deprecation) for 48 hours: 00:01 PST to 23:59 PST (midnight)

  • Monday, September 25, 2023: Fully remove support for building documentation without configuration file v2.

Adding a configuration file

If you have a project on Read the Docs that is not using a .readthedocs.yaml configuration file, you will need to create one as soon as possible to continue building your project.

Below is a minimal configuration template that you can copy and paste into your project. With this configuration file, your project should build successfully and will continue building after we deprecate our default build configuration in September 2023.

# .readthedocs.yaml
# Read the Docs configuration file
# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details

# Required
version: 2

# Set the version of Python and other tools you might need
  os: ubuntu-22.04
    python: "3.11"

# Build documentation in the docs/ directory with Sphinx
  configuration: docs/conf.py

# We recommend specifying your dependencies to enable reproducible builds:
# https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html
# python:
#   install:
#   - requirements: docs/requirements.txt

Additional help

There are some small differences between our build defaults and this configuration file template above. If you notice a build failure after making these changes, here are some things you can check while you tune your .readthedocs.yaml file:

  • The operating system has changed from Ubuntu 18.04 to Ubuntu 22.04

  • The new Ubuntu 22.04 may not have all the same system dependencies installed. If you need an Ubuntu package that’s not installed in the system, you can use build.apt_packages to install it.

  • The default Python version has changed from 3.7 to 3.11.

  • All the configuration done from the dashboard (Project Admin ‣ Advanced Settings ‣ Default settings) is ignored when using a configuration file. These settings have to be migrated to your project’s configuration file.

  • Git submodules are not cloned automatically. You can tell Read the Docs to clone them by using submodules.include config key.

  • HTMLZip format is not built by default. In case you want to keep building it, you can use the config key formats.

  • Node.js is not available by default. You can make it available by using build.tools.nodejs config key.

Starting with this suggested .readthedocs.yaml configuration file and taking into account these differences, you should be able to define a working configuration file and avoid breaking changes in the future.

See also

Configuration file tutorial

More usage examples and guidance can be found in our how-to for adding a .readthedocs.yaml configuration file.

What’s next?

In case you have some extra time, we recommend that you pin your project’s Python dependencies as well. This helps avoid surprise build errors when new packages are released. You can find more information in our guide, How to create reproducible builds.

Contact us

Contact us if you have any questions, and let us know if you are having trouble using a configuration file for any reason.