.NET 11 RC2 Is Here: Post-Quantum Crypto, C# UI for MAUI, and a Go-Live License

by Geth Author

Microsoft released .NET 11 Release Candidate 2 on October 13, 2026, carrying a go-live support license — meaning it's approved for production use now, not after November's general availability release. That's a meaningful signal from Microsoft: if you want to start running .NET 11 in real applications before the final release, RC2 is the version to do it with.

Post-quantum cryptography, experimentally

The headline addition is experimental support for quantum-resistant algorithms. RC2 adds composite ML-KEM and HPKE APIs — ML-KEM being one of the algorithms standardized by NIST for post-quantum key encapsulation. The "composite" approach means these algorithms can be used alongside classical cryptography as a hybrid, which is the practical deployment pattern most organizations will want as they begin migrating critical systems.

These APIs are experimental, flagged as such in the SDK, which means they can change between RC2 and general availability. But their inclusion now lets teams start designing against the interfaces and providing feedback before the final shape is locked in.

C# UI for .NET MAUI

For cross-platform developers, RC2 adds the ability to build .NET MAUI apps entirely in C# without touching XAML. This has been a long-standing ask from developers who prefer a code-first approach to UI — similar to what SwiftUI did for Apple's ecosystem, or what Jetpack Compose offers on Android. XAML remains fully supported, but teams that want to express their UI as code rather than markup now have an official path.

Hot Reload improvements ship alongside this, so iterating on a C# UI in development stays fast. The XAML authoring improvements in RC2 also improve the experience for teams staying with markup.

Other highlights

  • Incremental CBOR reading — useful for IoT and embedded scenarios where binary-encoded data needs to be parsed without loading everything into memory.
  • Configurable initial HTTP/2 concurrency — lets you tune the number of concurrent streams when a connection opens, relevant for high-throughput APIs.
  • NuGet minimum publication age — command-line configuration for enforcing a minimum age on NuGet packages in your project, a supply chain security measure.
  • Windows Forms KioskModeManager — a new component for building kiosk and locked-down touch UI applications on Windows.

What's not in RC2

There are no new C# language features in this release candidate. C# 14 features shipped in earlier previews; RC2 is focused on stabilizing what's already there. Some F# preview features still require an explicit language version opt-in.

Upgrading now or waiting?

The go-live license removes the main objection to early adoption: Microsoft will support you if something goes wrong in production. If your team is ready and your tooling supports it (Visual Studio 2026 Insiders or VS Code with C# Dev Kit), there's a reasonable case for starting the upgrade now and having the full release as a drop-in update in November. If you're running a stable stack and have no pressing need for RC2's specific additions, waiting three weeks for GA is equally fine.

General availability for .NET 11 is expected in November 2026 at the .NET Blog.