What's new in .NET 11

This article describes new features in .NET 11. It was last updated for Preview 4.

.NET 11 is currently in preview. The final release is expected in November 2026. You can download .NET 11 here.

.NET runtime

The .NET 11 runtime includes:

Updated minimum hardware requirements for x86/x64 and Arm64 architectures, requiring more modern instruction sets to improve performance and reduce maintenance complexity.
Runtime-native async (Runtime Async), which produces cleaner stack traces and lower overhead. Runtime Async no longer requires <EnablePreviewFeatures>true</EnablePreviewFeatures> for projects that target net11.0. The runtime libraries themselves are compiled with runtime-async=on.
JIT improvements for bounds check elimination, redundant checked context removal, switch expression folding, constant-folding SequenceEqual, and redundant branch elimination. There are also new Arm SVE2 intrinsics and improved hardware-intrinsic cost modeling.

The .NET 11 libraries include new APIs for:

Process expansion with run-and-capture helpers, fire-and-forget launches, SafeProcessHandle lifecycle methods, and tighter handle control.
Compression, including improved Base64 APIs, new methods for ZIP archive entries, Zstandard compression in System.IO.Compression, and CRC32 validation when reading ZIP entries.
System.Text.Json improvements, including generic type info retrieval, JsonNamingPolicy.PascalCase, per-member naming policy overrides, type-level ignore conditions, F# discriminated union support, and Utf8JsonWriter.Reset with options.
Built-in OpenTelemetry metrics for MemoryCache.
Discriminated-union scaffolding (UnionAttribute and IUnion) in System.Runtime.CompilerServices.
Tar archive format selection and GNU sparse format 1.0 support.
Console support for the FORCE_COLOR environment variable.
TLS handshake hardening and certificate-validation alerts on Linux.
HTTP/2 automatic downgrade for Windows authentication.

The .NET 11 SDK includes:

Smaller SDK installers on Linux and macOS through assembly deduplication, with additional savings by skipping crossgen for DotnetTools-only assemblies.
Improved CA1873 code analyzer with reduced noise and clearer diagnostic messages.
Support for creating and editing solution filters (.slnf) from the dotnet sln CLI.
File-based app support for #:include to split apps across multiple files.
A new dotnet run -e option to pass environment variables from the command line.
dotnet watch improvements, including Aspire app-host integration, automatic crash recovery, and device selection for MAUI and mobile projects.
OpenTelemetry replaces Application Insights for CLI telemetry.
Foundation for a NativeAOT entry point for the dotnet CLI.