Edge Dev for macOS cannot update on macOS 27 beta — Omaha server rejects update request with HTTP 400 #215

On macOS 27 beta (build 26A5425a), Microsoft Edge Dev cannot update using the in‑app updater. Manual PKG installation works normally, but the built‑in updater consistently fails with:

An error occurred while checking for updates: 9 (error code 0)

Unified logging shows that the update request is successfully sent to the Omaha update service, but the server responds with HTTP 400, causing the updater to abort before the install phase. This appears to be a server‑side OS version gating issue: Omaha does not recognize macOS version 27.0.0.

Environment:
• macOS 27.0 Beta (build 26A5425a)
• Microsoft Edge Dev (multiple versions tested, including 154.0.4251.0)
• In‑app updater (EdgeUpdater.app)

Steps to Reproduce:

1. Launch Microsoft Edge Dev on macOS 27 beta
2. Go to: Edge menu → Help and feedback → About Microsoft Edge
3. Allow the in‑app updater to check for updates
4. Observe error: 9 (error code 0)
5. Check unified logs for EdgeUpdater

Expected Behavior:
Edge Dev should download and install updates normally.

Actual Behavior:
The updater sends a valid Omaha request, including the OS version:
“os”:{“arch”:“arm64”,“platform”:“Mac OS X”,“version”:“27.0.0”}
The server responds with:
Omaha send error: 400
After receiving the 400 response, EdgeUpdater exits cleanly without attempting the update transaction.
Relevant Log Snippet
Sending Omaha request: {“request”:{”Oktay Sancak (@os)”:“mac”,”Updater Inc. (@Updater)”:“edgeupdater”, … “os”:{“arch”:“arm64”,“platform”:“Mac OS X”,“version”:“27.0.0”}, … }}
Omaha response received:
Omaha send error: 400
OnTaskComplete: error: 0
Emitted a UPDATER_PROCESS END event

Analysis:
The updater successfully launches, resolves DNS, establishes TLS, sends the update request, and receives a response. The failure occurs only after the server sees the OS version field. This strongly suggests that macOS 27.0.0 is not yet whitelisted in the Omaha update metadata for Edge Dev.
Because PKG installs work and Stable/Beta channels update normally, this appears isolated to the Dev channel’s update configuration.

Request:
Please update the Omaha server configuration to recognize macOS version 27.0.0 for Edge Dev, or advise if additional logging is required.