Image: Microsoft — the official .NET logo (via Wikimedia Commons, public domain).
TL;DR — .NET 11 new features explained: Microsoft shipped .NET 11 on 10 November 2026 with C# 15 union types, a faster SDK, MAUI on CoreCLR and EF Core 11. It is a Standard Term Support release with two years of support — and .NET 8 and .NET 9 lost support, so teams on those versions need a plan now.
📌 KEY HIGHLIGHTS
- Released 10 November 2026: Microsoft announced .NET 11 on the opening day of the free virtual .NET Conf 2026 (10–13 November). SDK 11.0.100 and runtime 11.0.0 are available now.
- C# 15 is the default language: union types, closed hierarchies, collection expression arguments, extension indexers, and labelled break and continue — no preview flag needed.
- A faster daily workflow: a Native AOT CLI host and a warm MSBuild server cut the startup overhead on everyday commands, and dotnet test gains run-level timeouts and failure limits.
- MAUI moves to CoreCLR: mobile and desktop apps now run on the same runtime as server code. ASP.NET Core adds async validation and OpenAPI 3.2; EF Core 11 requires .NET 11.
- The deadline that matters: .NET 8 and .NET 9 reached end of support on 10 November 2026, so they no longer receive security fixes. .NET 10 remains the supported LTS option.
What happened?
Microsoft released .NET 11 on 10 November 2026, announcing it on the .NET Blog at the opening of .NET Conf 2026, the free four-day virtual conference that runs until 13 November. The keynote, hosted by Scott Hanselman and the .NET team, started at 8 AM PST — 9:30 PM IST — with product-team sessions on 10–11 November and community sessions on 12–13 November.
.NET 11 is the year's major release, following .NET 10 a year ago. It is a Standard Term Support (STS) release with two years of support under Microsoft's .NET support policy. The release is the work of more than 7,000 contributors, and the wider ecosystem now counts over 589,000 unique packages on NuGet with more than 1.1 trillion package downloads.
The headline for most teams is not a feature but a date: .NET 8 and .NET 9 both reached end of support on 10 November 2026, the same day .NET 11 shipped. From now on, those versions get no security fixes, so any app still running on them is on borrowed time.
What's new in .NET 11 — the headline features
| Area | What's new |
|---|---|
| C# 15 | Union types, closed hierarchies, collection expression arguments, extension indexers, labelled break and continue |
| SDK and tooling | Native AOT CLI host, warm MSBuild server, smaller Linux and macOS installers, dotnetup toolchain manager (preview), dotnet test timeouts and failure limits |
| Runtime | JIT improvements, faster Native AOT interface dispatch, FP16 Half support on x64 and Arm64, crash-report logging on Linux and macOS |
| ASP.NET Core and Blazor | Asynchronous validation, OpenAPI 3.2 by default, SignalR authentication refresh, Blazor CacheView, circuit pause for idle tabs |
| .NET MAUI | CoreCLR is now the default runtime; XAML Incremental Hot Reload (preview); implicit XAML namespaces |
| Libraries | Zstandard compression, expanded Process APIs, LINQ FullJoin, System.Text.Json support for unions and JSON Lines |
| EF Core 11 | Requires .NET 11; leaner generated SQL, FullJoin translation, experimental SQL Server vector indexes and vector search |
| AI development | MCP server template, Microsoft.Extensions.AI, Microsoft Agent Framework, .NET Skills for coding agents |
C# 15 union types are the biggest language change in years. A union type is a value that must be one of a declared set of types — for example, a product lookup that returns either a Product or a ProductNotFound. The compiler then checks that every switch handles every case, so a forgotten outcome becomes a compile-time error instead of a runtime surprise. The case types do not even need to share a base class. Closed hierarchies solve the same problem from the other side: a closed class can only be derived within its own assembly, so the compiler knows every subtype in advance.
Image: Microsoft — the C# logo (via Wikimedia Commons, public domain). C# 15 is the default language version for projects targeting .NET 11.
Two things are still not stable, and the distinction matters. Runtime Async — which moves async suspension and resumption into the runtime for cleaner live call stacks and lower overhead — remains a preview feature in .NET 11. You can try it by opting in with <Features>runtime-async=on</Features> in a project targeting net11.0, but do not build production code on it yet. The separate C# memory-safety work also stays in preview, and the new Blazor AI components are experimental and prerelease throughout .NET 11.
Elsewhere, the SDK changes are the ones developers will feel daily: commands such as help and version queries can run without starting the managed CLI, the MSBuild server stays warm between invocations, and dotnet watch gains Aspire app-host integration and crash recovery. File-based apps can now grow across source files with #:include, and container publishing produces reproducible image digests.
Why it matters for developers
.NET is a workhorse of enterprise and IT-services engineering, including the large development teams across India that build and maintain business software on it. For those teams, the end-of-support date matters more than any single feature: an app on .NET 8 or 9 will keep running, but every new vulnerability found in it stays unpatched.
The MAUI change is the most structural one. With CoreCLR as the default runtime, mobile and desktop apps run on the same runtime foundation as server code, instead of a fork that lags behind — one runtime to learn, debug and keep patched. The catch is that the old Microsoft.Maui.Controls.Compatibility package no longer ships, so apps still referencing it must migrate off it as part of the upgrade.
The AI pieces are deliberately delivered as libraries rather than a new framework. Microsoft.Extensions.AI, the MCP server template (dotnet new mcpserver) and the Microsoft Agent Framework let an existing application add model access, tools and agents without rewriting it — a pragmatic path for teams that want AI features inside software they already ship.
Should you upgrade to .NET 11 now?
✅ Upgrade now if you are on .NET 8 or 9 — support has ended — or if you want C# 15 union types, MAUI on CoreCLR or EF Core 11. ⏳ Stay on .NET 10 if you want the longest support window and do not need the new features; try .NET 11 in CI first and move when you are ready.
| Version | Type | Status |
|---|---|---|
| .NET 11 | STS | Supported for two years from 10 November 2026 |
| .NET 10 | LTS | Supported — the long-term option |
| .NET 9 | STS | Support ended 10 November 2026 |
| .NET 8 | LTS | Support ended 10 November 2026 |
One warning before you upgrade: .NET 11 raises the minimum CPU requirements for x86/x64 and Arm64, so read the breaking-changes list first — especially if your build agents or deployment hosts run older hardware. Installing a new SDK alone does not retarget your app; you must update the target framework to net11.0 yourself.
How to get .NET 11
Download the .NET 11 SDK (11.0.100) from Microsoft's .NET download page, and use a compatible, up-to-date Visual Studio 2026 installation or Visual Studio Code with the C# Dev Kit. To try it with a console app:
dotnet new console -n HelloDotnet11 -f net11.0 dotnet run --project HelloDotnet11
For an existing application, Microsoft's upgrade path is: pin the SDK in global.json, retarget to .NET 11 while keeping platform-specific suffixes, update packages and workloads to compatible versions, review the breaking changes, then run your tests and measure the app under a representative workload. Validate your actual publishing mode, container base images and native dependencies before deploying — and if you were on a .NET 11 release candidate, move to the final SDK rather than staying on a prerelease build.
It has been a busy week for developer tooling: Rider 2026.3 shipped with day-one .NET 11 support, Visual Studio 2026 got its November update, and Node.js shipped a security release for versions 22, 24 and 26.
FAQs
Is .NET 11 released?
Yes. Microsoft released .NET 11 on 10 November 2026, announced on the .NET Blog at the opening of .NET Conf 2026. The final SDK is 11.0.100 and the runtime is 11.0.0, and both are available to download now.
What is new in .NET 11?
The headline additions are C# 15 union types and closed hierarchies, a faster SDK with a Native AOT CLI host and warm MSBuild server, .NET MAUI on CoreCLR, ASP.NET Core async validation and OpenAPI 3.2, EF Core 11, and AI building blocks including an MCP server template and the Microsoft Agent Framework.
Should I upgrade to .NET 11 or stay on .NET 10?
If you are on .NET 8 or 9, move now — support for both ended on 10 November 2026. If you are already on .NET 10, there is no urgency: it remains the supported LTS release, so upgrade to .NET 11 when you want C# 15 or the other new features, after testing in CI.
Is Runtime Async stable in .NET 11?
No. Runtime Async remains a preview feature in .NET 11. You can opt in per project with <Features>runtime-async=on</Features> without enabling preview features, but Microsoft advises testing your dependencies and diagnostics before adopting it, and the runtime libraries themselves are the only code built with it by default.
Takeaway
.NET 11 is a solid annual release — C# 15 union types are genuinely useful, the SDK is less of a waiting game, and MAUI finally shares the server runtime. But the real news is the calendar: .NET 8 and 9 are out of support, and that deadline, not the feature list, should set your upgrade priority.
If your apps still run on .NET 8 or 9, check the official support dates in the Sources below and plan the move this week — the SDK download and the upgrade guide are linked there.
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