[Windows-2025] LLVM will be updated to version 20 on 2025-06-06

[RaviAkshintala]

Breaking changes

LLVM will be updated from version 19 to version 20 on Windows 2025 image.

Target date

Image deployment will start on 2025-06-02 and will take 2-3 days.

The motivation for the changes

We'd like to keep images up-to-date with recent software updates.

Possible impact

If your builds depend on LLVM 19 they can be broken.

Platforms affected

• [x] Azure DevOps
• [x] GitHub Actions

Runner images affected

• [ ] Ubuntu 20.04
• [ ] Ubuntu 22.04
• [ ] Ubuntu 24.04
• [ ] macOS 13
• [ ] macOS 13 Arm64
• [ ] macOS 14
• [ ] macOS 14 Arm64
• [ ] macOS 15
• [ ] macOS 15 Arm64
• [ ] Windows Server 2019
• [ ] Windows Server 2022
• [x] Windows Server 2025

Mitigation ways

Customers should be able to use the latest version LLVM 20* N/A

[RaviAkshintala]

https://github.com/actions/runner-images/issues/11794

[RaviAkshintala]

The PR has been merged. We are closing this now.