C# - Category | .NET Blog

.NET 11 is here with C# 15, faster developer tools, runtime and library improvements, and new capabilities for web, mobile, desktop, and AI apps.
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Modernize your .NET apps for Windows Arm64 with the GitHub Copilot upgrade agent, from identifying migration blockers to planning and making code changes.
The GitHub Copilot SDK gives your application an agent runtime. BYOK lets you keep that runtime while sending model requests to your own Microsoft Foundry or Azure OpenAI deployment. Here is the complete C# setup.
Build Agentic UI with the new Blazor AI components for streamed content, tools, approvals, shared state, and generative experiences.
I am building a complete C# agent live, from a single call around an IChatClient to a production-ready, observable, governed agent, using the Microsoft Agent Framework harness in a 4-part Microsoft Reactor series.
Learn how C# unions and closed hierarchies work with System.Text.Json across ASP.NET Core Minimal APIs, MVC, SignalR, Blazor, and OpenAPI.
.NET 11 Release Candidate 1 is available with improvements across libraries, runtime, SDK, MSBuild, NuGet, C#, F#, ASP.NET Core, .NET MAUI, and Windows Forms.
C# 15 ships with .NET 11. It adds union types, closed hierarchies, a preview of the updated unsafe model, and a few smaller changes that remove everyday ceremony.
Route requests across models and providers natively in Microsoft.Extensions.AI with RoutingChatClient, SemanticRoutingChatClient, and FailoverChatClient — new experimental primitives for content-based routing, failover, and custom routing policies.
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