Microsoft rolls out .NET 11 Preview 7

Preview 7 highlights include new C# features, runtime-native async improvements, and major progress in CoreCLR on WebAssembly. Microsoft has announced the seventh preview release of the .NET 11 open source developer platform, with improvements ranging from tiered compilation for async methods and a milestone in bringing CoreCLR to WebAssembly. Developers can download Preview 7 from dotnet.microsoft.com. Production availability for .NET 11 is expected in November. Unveiled August 11, .NET 11 Preview 7 includes improvements across libraries, the .NET runtime, SDK, C#, ASP.NET Core, .NET MAUI, Entity Framework Core, F#, and Windows Forms, according to Microsoft. With this latest preview, runtime-async — the runtime’s built-in implementation of async/await — continues to close the gap with the compiler-generated state-machine model, according to Microsoft. Async versions of methods are now compiled through the tiered compilation pipeline. Async methods previously bypassed tiering and always ran the tier0 code, which was optimized for compilation speed rather than steady-state throughput. On the WebAssembly front, .NET 11 is bringing CoreCLR to WebAssembly with a portable interpreter-plus-R2R (ReadyToRun) model that reuses RyuJIT for ahead-of-time code generation. This configuration could start up in Preview 6, and now runs the CoreCLR libraries test suite end-to-end in Preview 7. Preview 7 also brings C# language and compiler updates including labeled break and continue. With C# 15, break and continue can name an enclosing loop or switch, allowing developers to exit or continue an outer construct directly from an inner one without threading state through a flag or resorting to goto. Also with C# 15, union types use the Try-Both matching approach. When a pattern is applied to a union value, the compiler first tests the pattern against the union instance itself; if that test fails, it tests the pattern against the union’s contained Value. Elsewhere in .NET 11 Preview 7: System.Net.Http gains three HttpContent wrappers that compress request bodies on the wire: GZipCompressedContent, BrotliCompressedContent, and ZstandardCompressedContent in the System.Net.Http namespace. dotnet test continues to pick up the device-oriented capabilities that dotnet run already has for MAUI, Android, and iOS projects. Preview 7 adds five new Blazor analyzers to help improve code quality. All are on by default and ship as Warning. .NET 11 Preview 7 follows the July 14 announcement of .NET 11 Preview 6.