What's new in ASP.NET Core in .NET 11 Preview 6 by Copilot · Pull Request #37334 · dotnet/AspNetCore.Docs

Copilot · 2026-07-10T20:17:51Z

Adds Preview 6 content to the cumulative "What's new in ASP.NET Core in .NET 11" article, generated from the dotnet/core release notes (dotnet/core#10456) via the whats-new-from-release-notes agent.

Note on parameters: The issue body listed PREVIEW = preview5, but the referenced source PR and the issue title are both Preview 6. Processed Preview 6 accordingly.

New include files

Minimal APIs — async-validation-minimal-apis-preview-6.md (IAsyncValidatableObject, AsyncValidationAttribute, Validator.ValidateObjectAsync), short-circuit-endpoints-attribute-preview-6.md ([ShortCircuit])
OpenAPI — openapi-3-2-default-preview-6.md (documents now target 3.2 by default)
SignalR — signalr-authentication-refresh-preview-6.md (token refresh without reconnect), signalr-cancel-hub-invocations-preview-6.md (client-side cancellation of non-streaming invocations)

Updated files

csharp-unions-preview-6.md — expanded to reflect the grown source: unions now span Minimal APIs, MVC/Razor Pages, SignalR JSON hub protocol, and Blazor, plus OpenAPI anyOf schema behavior and non-body binding limits.
aspnetcore-11.md — added [!INCLUDE] directives in the mapped sections; bumped ms.date to 07/10/2026; Breaking changes section left intact.

Excluded (per content rules)

Blazor Virtualize scroll-to-item — owned by the Blazor docs team; flagged, not authored here.
Bug fixes and the standalone contributors list — inline contributor thank-yous (@Youssef1313, @Porozhniakov) are preserved within their feature includes.

Conventions

Includes use H3 headings, no front matter, -preview-6 suffixes, relative Learn links, and present-tense phrasing. Verified <xref:> IDs are used where docs exist; brand-new Preview 6 APIs without published docs carry  markers for later conversion.

Internal previews

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

wadepickett · 2026-07-10T20:28:16Z

@tdykstra and @guardrex,
I started a draft for this. There may be udpates of the release notes to sync with between now and the final version. This does not include any update related to Blazor yet @guardrex since you usually like to do you own, but you can add to this draft if you want. As a reminder I am not available all next week. Tdykstra will take this over from here for any sync.

guardrex · 2026-07-10T20:44:29Z

@wadepickett ... Thanks!👍 Illona has a PR up, and I have one with only the Blazor C# union bits on it. I'll check next week to see what else Blazor needs. I'll review this Monday morning (without commits from me) to assist @tdykstra with the approval he'll need.

Edit pass. Co-authored-by: Wade Pickett <wpickett@microsoft.com>

guardrex

Approving with a handful of NIT suggestions.

guardrex

@tdykstra ... I left a few suggestions earlier and a date update for the main What's New article. I'll go ahead and see if it will let me commit them. This PR should be merged after mine because we want the Blazor What's New INCLUDES file pulled into the build here. I can't merge mine yet ... I need a sign-off on it.

UPDATE: Yes, I was able to commit the changes. We need my PR reviewed/merged first, and then this one ... and then merge to live if there's nothing else.

Co-authored-by: Luke Latham <1622880+guardrex@users.noreply.github.com>

guardrex · 2026-07-14T19:29:20Z

BTW, the CSRF middleware should probably be added to the Built-in middleware table at ...

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/middleware/?view=aspnetcore-10.0#built-in-middleware

wadepickett · 2026-07-19T21:47:09Z

@copilot resolve the merge conflicts in this pull request

…new-in-aspnetcore-11 # Conflicts: # aspnetcore/release-notes/aspnetcore-11/includes/csharp-unions-preview-6.md

Copilot · 2026-07-19T21:50:45Z

@copilot resolve the merge conflicts in this pull request

Resolved the merge conflict with main in 0c316f5. The only conflict was in csharp-unions-preview-6.md (both this PR and the merged Blazor PR #37322 edited it). I kept the Preview 6 detail (OpenAPI anyOf, ApiExplorer, [JsonUnion], SignalR limits) and incorporated main's updates: the C# 15 release-notes reference plus language-reference link, and the Blazor cross-reference paragraph.

General edit by Wade Co-authored-by: Wade Pickett <wpickett@microsoft.com>

wadepickett

Approved.

wadepickett · 2026-07-20T01:30:48Z

@tdykstra, need your review.

tdykstra

Approved but I left a few comments/suggestions.

tdykstra · 2026-07-20T02:10:18Z

+
+    public DateOnly Date { get; set; }
+
+    // IValidatableObject (synchronous) — this type validates asynchronously only.


This wording seems counterintuitive;please just take another look at this and others like it in this section and consider whether the code could benefit from more explanation.

@tdykstra: You are right, thanks for catching this. Copilot tried to condense it and took small section out and I didn't realize it. I need a Content fidelity & preservation rule added to the agent's skill file so it does not try to condense like this again. I created a tracking issue for this which I will follow up on later in this months sprint: #37349

tdykstra

Approved but left a few comments/suggestions.

Apply tdykstra review suggestions. Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

Enhance async validation support in minimal APIs with new DataAnnotations APIs. Update documentation to reflect changes in validation behavior and implementation examples.

Added a check for room availability in validation.

wadepickett · 2026-07-20T05:21:03Z

Closing and re-opening to force new build. Status checker was failing.

Fixed library link.

Removed reference circling back to the release notes.

wadepickett

Approved.

Initial plan

d5de904

Copilot AI assigned Copilot and wadepickett Jul 10, 2026

Copilot started work on behalf of wadepickett July 10, 2026 20:18 View session

Copilot AI linked an issue Jul 10, 2026 that may be closed by this pull request

Agent gen What's new in ASP.NET Core in .NET 11 Preview 6 #37333

Closed

Add What's New includes for ASP.NET Core .NET 11 Preview 6

9369471

Copilot AI changed the title ~~[WIP] Update What's new in ASP.NET Core in .NET 11 Preview 6~~ What's new in ASP.NET Core in .NET 11 Preview 6 Jul 10, 2026

Copilot finished work on behalf of wadepickett July 10, 2026 20:24

Copilot AI requested a review from wadepickett July 10, 2026 20:24

wadepickett requested a review from tdykstra July 10, 2026 20:25

wadepickett assigned tdykstra Jul 10, 2026

wadepickett requested a review from guardrex July 10, 2026 20:28

wadepickett reviewed Jul 11, 2026

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Edit pass. Co-authored-by: Wade Pickett <wpickett@microsoft.com>

guardrex approved these changes Jul 13, 2026

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[release-notes] ASP.NET Core in .NET 11 Preview 6 dotnet/core#10456

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Co-authored-by: Luke Latham <1622880+guardrex@users.noreply.github.com>

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Co-authored-by: Luke Latham <1622880+guardrex@users.noreply.github.com>

guardrex marked this pull request as ready for review July 14, 2026 18:31

Copilot started work on behalf of wadepickett July 19, 2026 21:47 View session

Merge remote-tracking branch 'origin/main' into copilot/update-whats-…

0c316f5

…new-in-aspnetcore-11 # Conflicts: # aspnetcore/release-notes/aspnetcore-11/includes/csharp-unions-preview-6.md

wadepickett reviewed Jul 20, 2026

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General edit by Wade Co-authored-by: Wade Pickett <wpickett@microsoft.com>

wadepickett approved these changes Jul 20, 2026

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tdykstra requested review from guardrex and tdykstra July 20, 2026 02:27

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wadepickett and others added 2 commits July 19, 2026 21:16

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Apply tdykstra review suggestions. Co-authored-by: Tom Dykstra <tdykstra@microsoft.com>

Update async validation documentation for minimal APIs

3fea3c4

Enhance async validation support in minimal APIs with new DataAnnotations APIs. Update documentation to reflect changes in validation behavior and implementation examples.

wadepickett reviewed Jul 20, 2026

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wadepickett added 2 commits July 19, 2026 21:42

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Implement room availability check in validation

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Added a check for room availability in validation.

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wadepickett reopened this Jul 20, 2026

Update async-validation-minimal-apis-preview-6.md

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Fixed library link.

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Removed reference circling back to the release notes.

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tdykstra requested review from guardrex and tdykstra July 20, 2026 16:00

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wadepickett merged commit 926a4ac into main Jul 20, 2026
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wadepickett deleted the copilot/update-whats-new-in-aspnetcore-11 branch July 20, 2026 17:39


		public DateOnly Date { get; set; }

		// IValidatableObject (synchronous) — this type validates asynchronously only.

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