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BC 29 Online Sandbox: F5 fails because AL Language does not support Debugger 9.0 #8354

Description

@Sathyasparta

Describe the bug

F5 publishing and debugging fails when connecting to a Business Central 29 Online Sandbox from Visual Studio Code.

The server requires Debugger 9.0, but the latest AL Language pre-release extension supports only up to Debugger 8.0.

Environment

  • Business Central version: 29.0.54011.55816
  • Environment: Online Sandbox
  • AL Language extension: 30.0.2813176 (Pre-release)
  • Server Runtime: 18.0
  • Server Web API: 7.0
  • Server Debugger: 9.0
  • AL supported debuggers: 1.0–8.0

Steps to reproduce

  1. Open an AL project in Visual Studio Code.
  2. Configure launch.json for a BC 29 Online Sandbox.
  3. Press F5.
  4. The connection fails during the /dev/metadata request.

Actual result

The following error appears:

This AL extension version for Visual Studio Code cannot be used with the specified server. Please update the AL extension from the Visual Studio Code marketplace.

Expected result

F5 should publish the extension and start debugging successfully.

Troubleshooting performed

  • Tested AL Language v18.
  • Tested AL Language v30 pre-release.
  • Installed the AL Language VSIX from BC 29.0.54011.56057 artifacts.
  • Restarted Visual Studio Code.
  • Confirmed AL compilation succeeds.
  • Confirmed deployment through the Business Central Admin Center API works.

Question

Is there an official AL Language build supporting Debugger 9.0 for Business Central 29 Online Sandbox environments?

Related issue: #8263

Activity

  1. MyhrerEnora commented on Oct 9, 2026

    @MyhrerEnora

    I get also the same error tried to use prerelease too

  2. MikeGlue commented on Oct 9, 2026

    @MikeGlue
    Contributor

    I updated my environment to this version and I can publish from VS Code:

    Platform 29.0.55365.0 + Application 29.0.54011.56023)

    Had to update via Admin Center --> Global Apps

    I am using v30.x of AL extension.

  3. ShreyChauhan29 commented on Oct 10, 2026

    @ShreyChauhan29

    Same issue here (Platform 29.0.55857.0). AL 18.1.2842859 from artifact 29.0.54011.56119 gets past the version check and publishes, but F5 then fails with a SignalR 400 on DebuggerHub/negotiate — details in microsoft/AL#8355. Marketplace versions details in microsoft/AL#8356.

  4. Sathyasparta commented on Oct 12, 2026

    @Sathyasparta
    Author

    Thank you so much, Mike Glue (@MikeGlue) , for sharing the solution! 🎉

    I updated the Base Application to version 29.0.54011.56023 through the Business Central Admin Center, and I can now successfully publish my AL extension from VS Code using AL Language v30.x.

    I really appreciate your help!

    Thanks also to Frank Myhrer (@MyhrerEnora) and ShreyChauhan29 for sharing your findings. Hopefully, this discussion will help others facing the same issue.

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