What's New in ASP.NET Core in .NET 11 Preview 4

[Copilot]

Fixes #37134

Adds Preview 4 feature coverage to the What's New article from dotnet/core@23c0684.

New include files

• OpenAPI: http-query-openapi-preview4.md — HTTP QUERY method in generated OpenAPI documents (contributor: @kilifu)
• OpenAPI: file-result-openapi-preview4.md — FileStreamResult/HttpResult types described as binary schemas (contributor: @marcominerva)
• Minimal APIs: endpoint-filters-binding-failures-preview4.md — filter pipeline runs on parameter-binding failures (contributor: @marcominerva)
• Miscellaneous: mcp-server-template-preview4.md — mcpserver template now bundled in SDK
• Miscellaneous: tls-handshake-observability-preview4.md — ITlsHandshakeFeature.Exception + UseTlsClientHelloListener middleware
• Miscellaneous: response-compression-vary-header-preview4.md — Vary: Accept-Encoding always emitted (contributor: @pedrobsaila)
• Miscellaneous: runtime-async-shared-framework-preview4.md — runtime-async enabled for shared framework libs

Blazor features present but excluded (handled by Blazor team)

• SupplyParameterFromTempData for Blazor
• Server-initiated Blazor Server circuit pause
• Virtualize viewport stability + AnchorMode
• Blazor WebAssembly service defaults template
• Blazor Web Worker template updates
• Smaller Blazor WebAssembly publish output

---

Internal previews

📄 File	🔗 Preview link
aspnetcore/release-notes/aspnetcore-11.md	What's new in ASP.NET Core in .NET 11

[wadepickett]

@guardrex, this What's New for v11p4 is still in draft. I will have it ready for review early tomorrow 5/12 Tuesday but suggestions welcome at anytime. Just a heads up so you know it is here. It did not address any new Blazor entires for this previwe since we always leave those to you:

• SupplyParameterFromTempData for Blazor
• Server-initiated Blazor Server circuit pause
• Virtualize viewport stability + AnchorMode
• Blazor WebAssembly service defaults template
• Blazor Web Worker template updates
• Smaller Blazor WebAssembly publish output

[guardrex]

Thx @wadepickett ... There are two left for me to work into my PR ...

• Server-initiated Blazor Server circuit pause
• Smaller Blazor WebAssembly publish output

I'll work those in this morning and ping you for additional review over there.

UPDATE: Working them now. Will chat with Ilona on the pause piece to get a good example into the coverage and gotchas. Will chat with Marek about the Blazor WASM publish output improvements because I haven't identified what that's referring to when looking at the SDK repo issues/PRs.

[wadepickett]

@tdykstra, need your review. This is a timely item.

[wadepickett]

Approved.