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Microsoft·Nov 10, 2026·v11·open source

.NET

.NET 11 is a major release of the .NET development platform featuring C# 15, runtime optimizations, and enhanced support for building AI-powered, agentic applications. It introduces significant language improvements like union types and closed hierarchies, alongside performance enhancements for web, mobile, and desktop development.

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overview

.NET 11 is a major release of the .NET development platform featuring C# 15, runtime optimizations, and enhanced support for building AI-powered, agentic applications. It introduces significant language improvements like union types and closed hierarchies, alongside performance enhancements for web, mobile, and desktop development.

key features
  • 01C# 15 support with union types and closed hierarchies
  • 02Native AOT CLI host and warm MSBuild server for faster development
  • 03AI-powered development tools including Microsoft.Extensions.AI and Microsoft Agent Framework
  • 04ASP.NET Core enhancements with OpenAPI 3.2 and asynchronous validation
  • 05.NET MAUI adoption of CoreCLR as the default runtime
  • 06Built-in Zstandard compression and new in-memory stream adapters
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