Windows: Daybreak Blue missing in 26.915.31029; rollback to 26.911.61220 restores it

What version of the Codex App are you using (From “About Codex” dialog)?

26.915.31029, mapped by archived release metadata to Windows MSIX package OpenAI.Codex 26.915.3509.0, x64. I recorded the package version using Get-AppxPackage before rollback, but did not capture its About dialog.

What subscription do you have?

pro 20x

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

After an automatic update to Windows package 26.915.3509.0, Daybreak Blue (gpt-daybreak-blue-latest) was unavailable in the desktop model picker, although Daybreak was available in the CLI.

On September 18, 2026, I backed up my local Codex data and downgraded to package 26.911.7940.0. After reopening the app, its About dialog showed 26.911.61220, Daybreak appeared again, and the app seemed to work normally. This makes the desktop update a suspected regression; I have not isolated its root cause.

While using the affected build (basically codex app), I also encountered refusals during cybersecurity work that I am authorized to perform. Daybreak was working for the same session in cli though so refusals were only in the codex app. I have not established whether that behavior shares a cause with the missing Daybreak option or which model handled each rejected request.

The missing picker option and its restoration after rollback are the concrete before/after observations. The relationship to the refusals needs investigation.

What steps can reproduce the bug?

Observed sequence on my machine:

1. Run Windows desktop package OpenAI.Codex 26.915.3509.0 x64 after the automatic update.
2. Open the desktop model picker and observe that Daybreak is unavailable.
3. Compare with the CLI, where Daybreak is available.
4. Downgrade the desktop package to 26.911.7940.0 and reopen the app.
5. Observe that Daybreak is available again.

I have not reinstalled the affected build for an additional reproduction because it blocked my work. Account/workspace identity, Windows build, and CLI version should be compared when investigating the difference.

What is the expected behavior?

The Windows desktop app should expose Daybreak when the account and workspace are eligible, consistently with the CLI. If it is unavailable because of an access or compatibility condition, the app should explain that condition.

Please investigate the picker regression and identify the Windows package version containing a fix so users who rolled back can update with confidence.

Additional information

• Installed package identity/version can be checked with:
  Get-AppxPackage OpenAI.Codex | Select-Object Name, Version, Architecture
• The official Windows update manifest still advertised 26.915.3509.0 when checked on September 18, 2026 at 10:46 UTC:
  https://persistent.oaistatic.com/codex-app-prod/windows-store-update.json
• A newer version number alone would not confirm that this regression is fixed.

Start by comparing the affected Windows package 26.915.3509.0 with the rollback package 26.911.7940.0, checking the desktop model picker against the CLI and inspecting the update manifest. Use Get-AppxPackage to verify package identity and version. Done means identifying the cause of Daybreak being absent and the Windows package version containing a confirmed fix.