What's new in .NET 11

This article describes new features in .NET 11. It was last updated for Preview 6.

.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.
Runtime Async performance improvements, including JIT compilation of a dedicated runtime-async version of synchronous task-returning methods, async continuations that opt out of ExecutionContext capture when no ambient state is in use, and tail-merged suspension points that reduce generated code size.
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, improved hardware-intrinsic cost modeling, and a faster Math.BigMul on x64 that emits a single MUL instruction.
In-process crash report logging on mobile platforms that captures the managed stack trace and runtime state before the process exits.
NativeAOT faster interface dispatch using a shared dispatch helper, reducing binary size at call sites and improving throughput for interface-heavy workloads.
SIMD lane construction and composition APIs (CreateGeometricSequence, Zip, Unzip, and the Concat family) across Vector128<T>, Vector256<T>, Vector512<T>, Vector64<T>, and Vector<T>.

For more information, see What's new in the .NET 11 runtime.

.NET libraries

The .NET 11 libraries include new APIs for:

Process expansion with run-and-capture helpers, fire-and-forget launches, SafeProcessHandle lifecycle methods, tighter handle control, and new ProcessStartInfo.StartSuspended for suspended starts and Process.TryGetProcessById for safe process lookup.
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, Utf8JsonWriter.Reset with options, SerializeAsyncEnumerable overloads for PipeWriter targets and top-level values (NDJSON) output, and serialization of C# union types.
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.
LINQ join improvements, including FullJoin and tuple-returning Join and GroupJoin overloads, across Enumerable, Queryable, and AsyncEnumerable.
A new X25519DiffieHellman class for X25519 key exchange.
Generic overloads on Random — NextInteger<T> and NextBinaryFloat<T> — that work with any numeric generic type.
EqualityComparer<T>.Create factory method that creates a comparer from a key selector.
QuicStream.Priority for HTTP/3 stream prioritization.
Video MIME type constants in MediaTypeNames.Video.
Four new Stream types (ReadOnlyMemoryStream, WritableMemoryStream, ReadOnlySequenceStream, StringStream) that wrap in-memory data without copying.
Asynchronous validation in System.ComponentModel.DataAnnotations via AsyncValidationAttribute, IAsyncValidatableObject, and new Validator.ValidateObjectAsync methods.
Activity tracing configuration using rules in Microsoft.Extensions.Diagnostics, enabling declarative control of Activity tracing without wiring up ActivityListener instances manually.
Cross-lane vector operations including CreateGeometricSequence, Zip, Unzip, and the Concat family on Vector128<T>, Vector256<T>, Vector512<T>, Vector64<T>, and Vector<T>.

For more information, see What's new in the .NET 11 libraries.

.NET SDK

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, and #:include ./libs/MyLib.dll to include compiled DLL references directly.
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.
NativeAOT CLI entry point that serves the full command surface—including --help for all built-in commands and tool/external-command launches—out-of-process from the AOT path, skipping managed CLI startup.
dotnet test improvements, including --no-dependencies, DOTNET_TEST_RUNNER environment variable, --use-current-runtime, --test-modules exclusion patterns, per-assembly test counts, and live display of in-flight tests.
Built-in test templates support xUnit v3 (defaulting to Microsoft.Testing.Platform) and NUnit with an opt-in --test-runner option.
Multi-architecture container image builds with Podman using the SDK's container publishing support.
TypeScript compilation outputs from Razor Class Libraries now integrate correctly with the Static Web Assets pipeline.
The dotnet CLI no longer suppresses the MSBuild build server when DOTNET_CLI_USE_MSBUILD_SERVER is unset, and the OTLP telemetry exporter activates on any standard OTEL_EXPORTER_OTLP_* environment variable.