dotnet-multi-targeting

You can use C# 14 features like `required` modifiers on older .NET target frameworks by applying polyfill strategies with PolySharp and SimonCropp/Polyfill. These tools backport language features and BCL APIs to ensure cross-framework compatibility.

Configuring a .csproj for multi-targeting involves specifying multiple Target Framework Monikers and setting up conditional package references. This approach ensures your library builds correctly across diverse .NET environments using TFM-specific source files.

To validate API compatibility across different .NET framework versions, use the `EnablePackageValidation` property and the `ApiCompat` tool. These mechanisms ensure API consistency across all targeted TFMs during the build process.

You need conditional compilation with `#if` directives in .NET multi-targeting to handle runtime behavior differences and platform-specific APIs. This approach allows your code to execute framework-specific logic based on the target TFM.

Yes, PolySharp works with .NET 8.0 and .NET 10.0 target frameworks. It enables you to use newer C# language features on older TFMs by providing the necessary polyfills for cross-framework development compatibility.

The limitations of using polyfills for multi-targeting in .NET libraries include the need to manually manage conditional compilation and validate API consistency using `EnablePackageValidation`. Polyfills only backport language features and BCL APIs, not underlying runtime platform capabilities.