.NET 11 has been released as a Standard Term Support version featuring C# 15, which includes the highly anticipated union types that help ensure exhaustive handling of case types at compile time. A significant change in this update is the runtime async functionality, which moves async/await transformations from the C# compiler to the JIT, resulting in cleaner stack traces and smaller binaries. The release also emphasizes AI integration through the Microsoft.Extensions.AI and the Microsoft Agent Framework, although some components remain experimental. As .NET 8 and .NET 9 reach the end of support on the same day, developers must decide whether to upgrade to .NET 11 or remain on .NET 10 LTS for continued support

.NET 11 Release: C# 15, Runtime Async, and an AI-First Stack

.NET 11 shipped today, as a Standard Term Support release with two years of servicing and the long-awaited C# 15 union types front and center. The runtime rework that matters most is runtime async, which moves the async/await transformation into the JIT for cleaner stack traces and smaller binaries, with defaults coming in .NET 12. AI got a coherent treatment this year through Microsoft.Extensions.AI, the Microsoft Agent Framework, and a built-in MCP server template, though the Blazor AI pieces stay experimental. The real urgency comes from .NET 8 and .NET 9 both ending support on that same day, so teams still on them need to decide now whether to jump to .NET 11 or ride it out on .NET 10 LTS.

.NET 11 Release: C# 15, Runtime Async, and an AI-First Stack @ NT Compatible