What's New in .NET 6? A Landmark LTS Release

Today marks a major milestone for the .NET community: the official release of .NET 6. This is a Long-Term Support (LTS) release, meaning it will be supported for three years, making it the ideal foundation for new and existing applications. .NET 6 is the culmination of the unification journey started with .NET 5, delivering a single, unified platform for building apps for the cloud, web, desktop, and mobile.

Packed with massive performance gains, new application models, and a host of productivity improvements in C# 10, .NET 6 is one of the most significant .NET releases ever.

Key Highlights of .NET 6

1. Massive Performance Gains

Performance is a feature, and .NET 6 is the fastest version of .NET yet. The team has made huge investments in optimizing the runtime, JIT compiler, and core libraries. File I/O has been re-architected, and there are significant improvements in areas like JSON serialization, LINQ, and collections, making .NET 6 a performance powerhouse.

2. Minimal APIs

Building fast, simple microservices in ASP.NET Core is now easier than ever with Minimal APIs. This new feature, combined with C# 10's top-level statements, allows you to create a fully functional web API in just a handful of lines of code, dramatically reducing boilerplate.

// A complete API in Program.cs
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello World!");

app.Run();

3. Hot Reload

Developer productivity gets a huge boost with Hot Reload. This feature allows you to modify your app's source code while it's running and see the changes applied instantly, without needing to restart the application. This creates a much tighter and more enjoyable development loop.

4. .NET MAUI (Multi-platform App UI)

.NET 6 marks the official arrival of .NET MAUI, the evolution of Xamarin.Forms. MAUI is a cross-platform framework for creating native UIs for Windows, macOS, iOS, and Android from a single C# codebase. It unifies the .NET ecosystem, allowing you to share more code than ever before across all your application types.

5. C# 10 Language Features

.NET 6 ships with C# 10, which is focused on simplifying syntax and reducing code ceremony.

• Global Using Directives: Declare using statements once for your entire project.
• File-Scoped Namespaces: Reduce indentation by declaring a namespace for an entire file on a single line.
• Record Structs: The benefits of records (immutability, value-based equality) are now available for value types.
• Constant Interpolated Strings: A small but welcome improvement for creating constant strings.

6. Source Generators

While not strictly a .NET 6 feature, the ecosystem around Source Generators has matured significantly. These allow libraries to generate code at compile-time, leading to significant performance improvements by avoiding runtime reflection. The built-in JSON serializer and logging frameworks in .NET 6 make heavy use of source generators.

A Unified and Mature Platform

With .NET 6, the vision of a single, unified .NET platform is now a reality. You can build any type of application—from high-performance cloud services to beautiful cross-platform native apps—with a single set of tools, languages, and libraries.

As an LTS release, .NET 6 provides a stable, reliable, and incredibly performant foundation for the next generation of .NET applications. It's an exciting time to be a .NET developer, and there has never been a better time to upgrade your existing applications or start a new one on .NET 6.