Microsoft releases .NET 11 with C# 15, a faster SDK, and end of support for .NET 8 and 9

Microsoft announced the release of .NET 11 on Tuesday, November 10, 2026, on the opening day of .NET Conf 2026, a free virtual conference running through November 13. The new version of the platform arrives with C# 15 as the default language, a faster SDK, and a range of features for web, cross-platform and AI-powered applications.

.NET 11 is a Standard Term Support (STS) release, with two years of support. .NET 10 remains the Long Term Support (LTS) option. On the same day as the launch, .NET 8 and .NET 9 reached end of support and no longer receive fixes — teams still on those versions need to move to .NET 10 or .NET 11 to keep receiving updates.

What is new in .NET 11

  • C# 15: union types and closed hierarchies, which let the compiler check that every possible case has been handled; plus collection expression arguments, extension indexers, and labeled break and continue.
  • Faster SDK: a Native AOT CLI host, enabled by default, and an MSBuild server that stays warm between invocations, reducing startup time for everyday commands. The dotnet run -e command passes environment variables from the command line.
  • ASP.NET Core: asynchronous validation, OpenAPI 3.2 as the default version for generated documents, and new features for Blazor and SignalR, including authentication refresh without reconnecting.
  • AI and agents: Microsoft.Extensions.AI (MEAI) for model access, MCP for tool integration, Microsoft Agent Framework (MAF) for agents and workflows, plus an MCP server template in the SDK (dotnet new mcpserver).
  • .NET MAUI: CoreCLR becomes the default runtime, putting mobile and desktop apps on the same runtime foundation as other workloads.
  • Entity Framework Core 11: requires .NET 11 and improves how queries translate to SQL, with FullJoin support in LINQ and experimental vector search for SQL Server.
  • Libraries: Zstandard compression in System.IO.Compression, new process APIs, C# union support in System.Text.Json, and JSON Lines output.

End of support for .NET 8 and .NET 9

The most urgent detail of the launch is the calendar: .NET 8 and .NET 9 reached end of support on November 10, 2026. Microsoft recommends moving to a supported release — .NET 11 for the latest features, or .NET 10 if the LTS lifecycle fits better. The final .NET 11 release is version 11.0.0, with SDK 11.0.100, and requires Visual Studio 2026 (version 18.12) or Visual Studio Code with C# Dev Kit.

How to get started

To create and run a console app on .NET 11:

dotnet new console -n HelloDotnet11 -f net11.0
dotnet run --project HelloDotnet11

Not everything is finalized: Runtime Async, which moves async suspension and resumption into the runtime, remains a preview feature and must be enabled per project. The Blazor AI components are also experimental and prerelease throughout the .NET 11 cycle.

According to Microsoft, .NET 11 is the work of more than 7,000 contributors. The ecosystem has over 589,000 unique packages on NuGet and more than 1.1 trillion downloads.

Image credit: collage of the avatars of the more than 7,000 .NET 11 contributors, published on the official .NET Blog (Microsoft).

Sources

Transparency: this article was prepared with the assistance of artificial intelligence, based on public posts and internet sources. Please consult the original sources to confirm the information.

By Muse