.NET 9 - Release

[jamesmontemagno]

We are pleased to announce the general availability of .NET 9.

Read about the final release on the .NET Blog announcement.

You can find a detailed overview of new features across .NET 9 in our documentation:

• What's new in .NET 9: Runtime, Libraries, and SDK
• What's new in C# 13
• What's new in F# 9
• What's new in ASP.NET Core
• What's new in .NET Aspire
• What's new in .NET MAUI
• What's new in EF Core
• What's new in WPF
• What's new in Windows Forms

Get started

To get started with .NET 9, install the .NET 9 SDK.

If you're on Windows using Visual Studio, we recommend installing the latest Visual Studio 2022. .NET 9 is now can be installed directly through the Visual Studio installer starting with Visual Studio 2022 17.12.

You can also use Visual Studio Code and the C# Dev Kit extension with .NET 9.

You can find .NET 9 Installer & Binaries on GitHub.

Release Notes

Release notes are available for changes between .NET 9 RC2 and this release:

• Libraries
• Runtime
• SDK
• .NET MAUI
• ASP.NET Core
• C#
• EF Core and Data
• F#
• WinForms
• WPF

Celebrate the release of .NET 9 at .NET Conf 2024 - November 12th -14th.

[Atulin]

Very available indeed

[GerardSmit]

This depends on microsoft/winget-pkgs#190763. You can subscribe to this PR to see when it's available in WinGet.

[Atulin]

Sure, of course. I just find it weird that Microsofts builds the hype around a release first with "HOLY SHIT GUYS .NET 9 IS AVAILABLE TODAY DOWNLOAD IT NOW IT'S NOW HOOOOLY DOWNLOAD IT RIGHT THIS INSTANT" kinds of blogposts, articles, and discussions... only for the download page and Winget to show only RC2.

The download page now, thankfully, has the 9.0.100 properly, but Winget is still missing... and yet the general messaging is "GET IT NOW"

Just maybe, you know, fully release things first, then write the articles

[jamesmontemagno]

Thanks for the comment and feedback here. Will work with the team and figure out what is going on here, it is a challenge with many moving parts as to when to make the post as bits are available, but will work to make it much more granular.

[jamesmontemagno]

@Atulin winget packages should now be available

[craigs100]

Thanks but it's not on "General" release though is it? Let me explain.....

I develop Umbraco websites using the .Net Core SDK's on Linux Mint. Following your (Microsoft's) instructions not to mix repos between MS & the distro's repos, I opted to go with the MS repos. I generally need the SDK's asap, plus I want to be sure I'm using an approved SDK version as I don't want any surprises when I deploy code to servers.

From .NET V9, you're now not providing the Linux versions for download if the Linux Distro of choice provides a version in their repo.

This now gives me a massive problem. I need versions that aren't available on the Linux Mint repo which includes V6 and V9.

Could you please reconsider this?

The distro's aren't particularly quick making new SDK's available. Also, do you know if the versions they do provide are 1 to 1 compatible with yours.

Thanks for reading so far. I'm extremely keen for answers as it's my livelihood being affected.

Regards.

[bettwedder]

With .NET 9 I started getting System.AccessViolationException crashes in a .NET MAUI application that was rock solid before the upgrade. The issue is inside a function that reads and sums an array in parallel. The program runs the function that throws this error twice each millisecond and will run for anywhere from 25 minutes to 2 hours without it encountering the error. An example message is at the bottom of this post. While writing this post I got a new crash reason:

Application: MyMauiApp.exe
CoreCLR Version: 9.0.24.52809
.NET Version: 9.0.0
Description: The process was terminated due to an internal error in the .NET Runtime at IP 0x00007FFE80BBEA8B (0x00007FFE808D0000) with exit code 0xc0000096.

Previous Crash Errors:

CoreCLR Version: 9.0.24.52809
.NET Version: 9.0.0
Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Stack:
at System.Runtime.ExceptionServices.InternalCalls.g____PInvoke|0_0(System.Runtime.StackFrameIterator*, Void*, Int32, Boolean*)
at System.Runtime.ExceptionServices.InternalCalls.g____PInvoke|0_0(System.Runtime.StackFrameIterator*, Void*, Int32, Boolean*)
at System.Runtime.EH.DispatchEx(System.Runtime.StackFrameIterator ByRef, ExInfo ByRef)
at System.Runtime.EH.RhThrowHwEx(UInt32, ExInfo ByRef)
at MyNamespace.MyClass+<>c__DisplayClass96_0.b__0(Int32)
at System.Threading.Tasks.Parallel+<>c__DisplayClass19_0`2[[System.__Canon, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Int32, System.Private.CoreLib, Version=9.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].b__1(System.Threading.Tasks.RangeWorker ByRef, Int64, Boolean ByRef)
at System.Threading.Tasks.TaskReplicator+Replica.Execute()
at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(System.Threading.Thread, System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Threading.Tasks.Task.ExecuteWithThreadLocal(System.Threading.Tasks.Task ByRef, System.Threading.Thread)
at System.Threading.ThreadPoolWorkQueue.Dispatch()
at System.Threading.PortableThreadPool+WorkerThread.WorkerThreadStart()

[julealgon]

You should consider opening an issue on the .NET MAUI repo.

[bettwedder]

You should consider opening an issue on the .NET MAUI repo.

You are correct, I just opened it in the runtime repo as the error seems to be non-MAUI related. I can't get it to happen in debug mode which leads me to believe it has something to do with runtime optimizations. Should I delete the one here?

[julealgon]

Should I delete the one here?

Probably not needed. I would link your runtime issue here though for tracking.