Microsoft has rolled out the first preview of .NET 10, a major new version of the company’s flagship software development platform. Likely to arrive as a production release in November, .NET 10 introduces C# 14 and adds major enhancements to the .NET runtime, SDK, libraries, ASP.NET Core, Blazor, and .NET MAUI.

Key Features of .NET 10 Preview 1

• C# 14: First-class support for System.Span<T> and System.ReadOnlySpan<T>, new implicit conversions, and parameter modifiers for lambda expression parameters.
• .NET 10 Runtime: Reducing abstraction overhead, expanding JIT compiler’s ability to de-virtualize method calls, and stack-allocating small arrays.
• .NET 10 Libraries: Introducing APIs that work with spans of characters, improved performance for ZipArchive, and new APIs for transformation matrices.
• F#: Better handling of generic unmanaged structs and a type conversions cache.
• .NET 10 SDK: NuGet Audit feature for pruning unused package references.
• Visual Basic: Adds unmanaged constraint support and respects OverloadResolutionPriorityAttribute.
• ASP.NET Core: Support for generating OpenAPI 3.1 documents, now with YAML format support.
• Blazor: RouteAttribute supports route syntax highlighting.
• Entity Framework: Adds first-class LINQ support for the LeftJoin method.
• .NET MAUI: Ships as a .NET workload and multiple NuGet packages.

Availability

.NET 10 Preview 1 can be downloaded from the official site.

Microsoft’s .NET 10 follows last November’s release of .NET 9, continuing improvements across the development platform.