.NET 11 Preview 2: Runtime Async Matures, SDK Gets Leaner, and ASP .NET Core Gets Observability Right

Runtime: Async Gets a Rethink

The headline runtime update in Preview 2 is Runtime Async V2, a significant evolution of how async execution is handled at the runtime level. Alongside that, JIT compiler improvements continue to reduce overhead and improve execution efficiency, and cached interface dispatch brings faster virtual method resolution in performance-sensitive scenarios.

For teams running high-throughput APIs or backend services, these are the kinds of improvements that compound over time without requiring code changes.

SDK: Smaller, Smarter Installs

The .NET SDK now ships with smaller installers on Linux and macOS, which is a welcome change for teams managing CI/CD environments and Docker-based pipelines where install size and speed matter. Preview 2 also brings code analyzer improvements and new SDK warnings and build targets, helping developers catch issues earlier in the development cycle.

ASP.NET Core & Blazor: OpenTelemetry and OpenAPI

ASP.NET Core gains native OpenTelemetry tracing support, making it easier to instrument applications without third-party packages. Blazor picks up TempData support, and the release adds OpenAPI 3.2.0 support alongside a new .NET Web Worker project template. Performance improvements round out the ASP.NET Core updates.

F#: Quality of Life Improvements

F# developers get several useful additions: simplified DIM interface hierarchies, overload resolution caching, the #elifpreprocessor directive, and a new partitionWith function for collections. These are incremental but meaningful improvements for teams working in F#.

.NET MAUI: Performance and Stability

.NET MAUI receives TypedBinding performance improvements, Map control updates, immutability annotations for Color and Font, and VisualStateManager API consistency improvements. On the Android side, dotnet run gets fixes and improvements, and CoreCLR now requires API 24 or higher. There's also experimental CoreCLR support for iOS, Mac Catalyst, macOS, and tvOS, worth watching as it matures.

Libraries: Small Wins That Add Up

Matrix4x4.GetDeterminant is approximately 15% faster, Tar archive format selection gives developers more control over archive output, and System.Text.Json gains a generic GetTypeInfo API for more flexible type handling at runtime.

Our Take

Preview 2 reads like a team executing well on a plan. Runtime Async V2 is the feature to track, it represents a genuine architectural shift in how async works in .NET, and subsequent previews will tell us whether it delivers on its potential.

For everyone else, the practical wins are real: native OpenTelemetry support in ASP.NET Core, smaller SDK installers, and continued JIT improvements are the kinds of changes that improve day-to-day development without requiring any work on your end.

If you want to explore the runtime improvements, Preview 2 is a reasonable place to start. And if your application handles PDFs, barcodes, spreadsheets, or document processing, the Iron Suite libraries are actively tested against .NET preview releases, so you can build on the latest platform without worrying about compatibility.

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