Update macOS Sequoia to 15.6.1

[jnewland]

Tool name

macOS Sequoia

Tool license

Apple

Add or update?

• Add
• Update

Desired version

15.6.1

Approximate size

No response

Brief description of tool

Was surprised to find this not available even on macos-latest when I went to try to install the Xcode RC manually while #12991 takes its time to roll out. Xcode RC requires 15.6, which was released in late July. 15.6.1 has also subsequently been released, so there are two security releases pending:

• https://support.apple.com/en-us/124149
• https://support.apple.com/en-us/124927

Could you please also clarify the upgrade policy for OS minor releases? I spent some time on the homepage and couldn't figure that out.

URL for tool's homepage

https://support.apple.com/en-us/124927

Provide a basic test case to validate the tool's functionality.

xcodes list | grep 17A321

Platforms where you need the tool

• Azure DevOps
• GitHub Actions

Runner images where you need the tool

• 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
• Windows Server 2025

Can this tool be installed during the build?

Tool installation time in runtime

No response

Are you willing to submit a PR?

Yes

[erik-bershel]

Hey @jnewland!

15.6 update is progress now as required for Xcode 26 RC. Will be delivered soon. Stay tuned!

[jnewland]

Thank you for the update. Unfortunately, I also see that many macOS image update PRs from the past few days remain open and seem stuck. I've taken this as a sign that this update won't be available soon and am making other plans to try to be ready for launch day.

I spent a bunch of time yesterday and this morning spinning my wheels because a) I assumed this OS version would already be available since it contained security updates and b) couldn't find any indication that the upgrade was in-flight.

Can you please clarify the target upgrade policy for OS patch releases to help others avoid confusion here going forward?

[erik-bershel]

Can you please clarify the target upgrade policy for OS patch releases to help others avoid confusion here going forward?

I'm not sure we have a public SLA for this type of update. 🤔 I'll note separately that in general we try to update OS as soon as possible, which usually takes from a week to two. The current situation is rather an exception and is a consequence of an internal failure.

[erik-bershel]

macOS-15-arm64 image (aka macos-15 label aka macos-latest label for GH Actions) update:

• macOS 15 arm64 (20250911) Image Update #13006

Upd: it's 15.6 based

[gregneagle]

Hoping that will be merged soon. Today, maybe? :-)

[erik-bershel]

Today, maybe? :-)

Can't promise. In the next 24 hours let's say.

[erik-bershel]

Xcode 26 Release + simulator runtimes on macOS 15.6.1 arm64 image update:

• macOS 15 arm64 (20250916) Image Update #13029