[macOS] Support policy changes; Xcode 14 and 16 will be removed from macOS 14 on November 4

[erik-bershel]

Breaking changes

Current support policy:

- all OS compatible versions side-by-side
- for beta, GM versions - latest beta only
- old patch versions are deprecated in 3 months

New support policy:

- only one major version of Xcode will be supported per macOS version
- all minor versions of the supported major version will be available
- beta and RC versions will be provided "as-is" in the latest available macOS image only no matter of beta/GA status of the image
- when a new patch version is released, the previous patch version will be replaced

• What does it means in general terms? Starting from the specified date, all minor versions of Xcode 14 and Xcode 16 will be removed from the macOS-14 image.
• What about other images? These changes will not affect macOS-12 and macOS-13 images. The changes will affect macOS-14 and all subsequent images. As a result, macOS-14-based images will contain only Xcode 15.x versions, macOS-15 images will contain only Xcode 16.x versions, and so on.
• What happens when a new major Xcode beta is released and there is no next revision of the macOS image? Such a beta will be shipped as part of the latest macOS image that supports this Xcode, until the next base macOS image is released, for example: Xcode 16 was shipped as part of macOS-14 until we released macOS-15.

Target date

November 4, 2024

The motivation for the changes

Recently, mainly due to the introduction of the new visionOS platform, macOS-based images have grown to such sizes that they are becoming more difficult to maintain, and users are experiencing difficulties with available disk space, which is critical for completing builds. Parent issue:

• https://github.com/actions/runner-images/issues/10511

Possible impact

Workflows based on macOS-14 will stop running if they depend on Xcode 14 and/or Xcode 16

Platforms affected

• [X] Azure DevOps
• [X] GitHub Actions

Runner images affected

• [ ] Ubuntu 20.04
• [ ] Ubuntu 22.04
• [ ] Ubuntu 24.04
• [ ] macOS 12
• [ ] macOS 13
• [ ] macOS 13 Arm64
• [X] macOS 14
• [X] macOS 14 Arm64
• [X] macOS 15
• [X] macOS 15 Arm64
• [ ] Windows Server 2019
• [ ] Windows Server 2022

Mitigation ways

Users whose workflows depend on Xcode 14 and/or Xcode 16 will be forced to use the macOS-13 image for Xcode-14 and the macOS-15 image for Xcode-16, respectively. Be aware that macos-13 YAML label refer to Intel-based image.