.NET interactive going away, need replacement

[rmunn]

Currently the Dockerfile installs the Microsoft.dotnet-interactive tool, but Microsoft has chosen to deprecate the tool as of April 24, 2026 (just two days from now as I write this). It's unclear whether the tool will continue to be installable or will be removed, but the line "You can continue using .NET Interactive as a Jupyter kernel as is in other Jupyter frontends after its deprecation date if you don't uninstall it" (emphasis mine) doesn't look promising.

A different tool is likely to be needed to replace dotnet interactive. I don't currently have any recommendations, sorry.

[nojaf]

@nhirschey any thoughts on this?

[github-actions]

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Thanks for flagging this, @rmunn! A quick clarification on the immediate risk:

Short-term (after April 24): The pinned version 1.0.410202 in the docs/Dockerfile will still be installable after deprecation. NuGet deprecation marks a package as deprecated in the gallery UI but does not remove it — dotnet tool install --global Microsoft.dotnet-interactive --version 1.0.410202 will continue to work. So the Dockerfile won't break on April 24.

Longer-term concerns (both real):

1. The .NET 7.0 SDK Docker image (FROM mcr.microsoft.com/dotnet/sdk:7.0) has been EOL since May 2024. This is arguably the more urgent issue — the base image may stop receiving security patches from Microsoft.
2. Compatibility: Updating to a current .NET SDK (8.0 LTS / 9.0 / 10.0) would require a compatible version of Microsoft.dotnet-interactive. The tool's versioning history shows versions targeting .NET 6/7 vs .NET 8. With the tool now deprecated, there may not be a .NET 10-compatible release ever published.

The Dockerfile is only used for mybinder.org (the Binder launch badge on the docs), not in CI. So it's important for interactive docs exploration but not for the build pipeline.

Possible paths forward:

• Pin a newer dotnet-interactive version targeting .NET 8 and update the SDK to 8.0 LTS
• Investigate [Fable REPL]((fable.io/redacted) or other browser-based F# alternatives for the Binder use case
• Consider whether mybinder.org support is still actively used/needed

Happy to open a draft PR to at least update the base image to .NET 8 if that would be helpful — though we'd need to verify dotnet-interactive compatibility first.

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[nhirschey]

We don't depend on .net interactive to generate literate notebooks in the build pipeline. I think it's still unclear what the future of jupyter notebooks is in .NET, so for now I'd keep our generation code and maybe just caution in our docs that .net interactive is deprecated. The jupyter notebook FSharp.Formatting outputs could be used by other jupyter kernels (TBD what those kernels would be).

There's a recent open issue to continue development of .NET interactive kernel as part of .NET Foundation dotnet-foundation/projects#515

Regarding the docker image, maybe \repo-assist could confirm [edit: ok apparently it did above] but I think that's only used for binder integration, where you click on a F# formatting page link for "run this in binder" and it goes to the binder website, creates an image, and build things (kinda like google colab). I believe dsyme built that integration. I'd suggest leaving it for now, until it actually breaks. Though it could plausibly be updated one last time to .NET 10.

[nhirschey]

And the "replacement" might be a world where you ask your agent to build a .md or .html dashboard of the results generated by an fsx file. that's what I've done lately.