What's new in .NET 11

This article describes new features in .NET 11. It was last updated for release candidate 1 (RC 1).

.NET 11 is currently in release candidate. General availability 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.
Runtime Async tiered compilation, task and value-task factory intrinsics, and implicit tailcall improvements that reduce warm-up allocations and speed up common await paths.
JIT improvements for bounds check elimination, redundant checked context removal, devirtualization, 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.
CoreCLR on WebAssembly now runs the libraries test suite end to end, and the runtime adds AVX-VNNI-512 hardware intrinsics for vectorized multiply-add workloads.
In-process crash report logging that captures the managed stack trace and runtime state before the process exits, available on mobile platforms as well as Linux and macOS.
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>.
Hardware FP16 instructions for Half arithmetic and conversions on x64 and Arm64.

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, new ProcessStartInfo.StartSuspended for suspended starts, Process.TryGetProcessById(Int32, Process) for safe process lookup, and Process.Signal(PosixSignal) with ProcessExitStatus for signaling processes and inspecting how they exited.
Compression, including improved Base64 APIs, new methods for ZIP archive entries, Zstandard compression in System.IO.Compression, CRC32 validation when reading ZIP entries, and a Reset() method on the streamless Deflate, ZLib, and GZip encoders and decoders.
New numeric APIs, including IEEE 754 decimal floating-point types (Decimal32, Decimal64, and Decimal128), INumberBase<TSelf>.TryParsePartial for delimiter-aware parsing, and generic Complex<T>.
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, serialization of C# union types with the new JsonUnionTypeStructuralClassifier, built-in converters for BFloat16 and the new decimal floating-point types, and base64 schema metadata from JsonSchemaExporter.
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, certificate-validation alerts on Linux, channel binding validation on Unix, and an experimental caller-driven TLS session API (TlsBufferSession and TlsSocketSession).
Networking additions, including HTTP request-body compression wrappers, configurable HTTP connection eviction, and typed DNS record resolution APIs on Windows, Linux, and macOS through Dns and the new DnsResolver class.
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, and unpadded AES Key Wrap support (EncryptKeyWrap/DecryptKeyWrap) on Aes.
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.
BitArray constructors that accept ReadOnlySpan<bool>, ReadOnlySpan<byte>, and ReadOnlySpan<int>.
Asynchronous validation in System.ComponentModel.DataAnnotations via AsyncValidationAttribute, IAsyncValidatableObject, and new Validator.ValidateObjectAsync methods, along with asynchronous Microsoft.Extensions.Options validation through IAsyncStartupValidator.
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 to include compiled DLL references directly, plus Native AOT build-output reuse and dotnet format support for file-based apps.
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.
NativeAOT CLI and the MSBuild server are now enabled by default.
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.
dotnet test support for Android, iOS, macOS, and Mac Catalyst test projects, with device selection and new androidtest, iostest, macostest, and maccatalysttest templates.
Additional dotnet test run-level options, including --timeout, --maximum-failed-tests, --results-directory-layout per-module, and an experimental affected-test workflow, along with traversal-project support, JSON output for --list-tests, and artifact post-processing for multi-module runs.
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.
Container publishing now prefers platform-native local runtimes (wslc on Windows and container on macOS) before Docker and Podman, produces reproducible image digests through SOURCE_DATE_EPOCH, and skips redundant layer uploads when the target manifest already exists.
TypeScript compilation outputs from Razor Class Libraries now integrate correctly with the Static Web Assets pipeline.
dotnet format limits .editorconfig discovery in folder mode to the ancestor directories of included files.
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.