Microsoft Issues .NET 9 RC1

Microsoft has released the first of two release candidates for .NET 9 ahead of its final release on November 12.

“.NET 9, the successor to .NET 8, has a special focus on cloud-native apps and performance,” the Microsoft Learn website explains. “It will be supported for 18 months as a standard-term support (STS) release.”

Given where we are in the schedule, it’s not surprising that there’s not much new in this release, though I keep hoping in vain to see something–anything–related to the Windows Presentation Foundation (WPF) work that was announced in May but never updated since then. But RC1 does include improvements to the .NET WebSockets APIs, new compression options, advanced SignalR tracing, and updates to text alignment in .NET MAUI, and some other small changes.

More broadly, .NET 9 will ship with C# 13, a new attribute model for the .NET runtime that supports feature switches and trimming, new SDK-level features like workload sets, ML.NET 4.0, the .NET Aspire Preview, minor improvements to ASP.NET Core and .NET MAUI, and other improvements.

You can download the .NET 9 Release Candidate 1 SDK from the .NET website as with previous releases, but it’s also available directly from the Visual Studio Installer when you upgrade to Visual Studio 2022 v17.12 Preview 2. This release is also compatible with Visual Studio Code and the C# Dev Kit extension.