.NET 9 Preview 3

[jamesmontemagno]

We are pleased to announce the release of .NET 9 Preview 3.

Here's a summary of what's new in .NET Libraries, Runtime, & SDK in this preview release:

• TimeSpan.From overloads
• Added PersistableAssemblyBuilder type in System.Reflection.Emit
• Faster exception handling
• Inlining Improvements: Shared Generics with Runtime Lookups
• Terminal Logger Usability

For details on these new features and more see the

• .NET Libraries Release Notes
• .NET Runtime Release Notes
• .NET SDK Release Notes

You can find detailed release notes for additional features in .NET 9 Preview 3 below:

• .NET Data & EF Core
• .NET MAUI
• ASP.NET Core

You can re-use and re-mix release notes per license information.

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 preview, or get started with Visual Studio Code and the C# Dev Kit extension.

You can find .NET 9 Preview 3 Installer & Binaries on GitHub.

Team Announcements & Discussions

Discuss this release with the product teams on GitHub through the announcements for this release.

• .NET MAUI
• ASP.NET Core
• Libraries & Runtime
• Containers
• Source-build

Stay up-to-date with .NET 9

You can stay up-to-date with all the features of .NET 9 with:

• What's new in .NET 9
• What's new in ASP.NET Core
• What's new in .NET MAUI
• What's new in EF Core
• Breaking Changes in .NET 9
• .NET 9 Releases

For .NET 9 previews we are utilizing GitHub Discussions to make announcements. For more information read our discussion.

Stay up to date by subscribing to the RSS feed for all release announcements.

You can find a full list of release notes and discussions for all preview releases in the Release Index thread.

[masonwheeler]

Added PersistableAssemblyBuilder type in System.Reflection.Emit

Finally! 🎉 I've been waiting 9 years for this API! I'll try and get this working, and report back with feedback.

[RealDoigt]

At last there's hope for the Boo language yay

[buyaa-n]

I'll try and get this working, and report back with feedback.

Thanks, that would be very helpful. Also, in case you haven't looked into PDB support proposal and have feedback please let us know.

[masonwheeler]

@buyaa-n Yeah, I've seen that. That API is definitely going to be part of my tests of this system.

[SystematicChaos012]

Will generic UnsafeAccessor be published in Preview 4?

[jkotas]

Yes. cc @AaronRobinsonMSFT

[AaronRobinsonMSFT]

It is already available in nightly builds. It would be most helpful for people to work with it and let us know about bugs or where the documentation is insufficient.

[Jaziel-Ali]

Uep

[eder-em]

@jamesmontemagno please fix this horrible top 1st MOST COMMENTED issue on dotnet MAUI
dotnet/maui#7354

[InternalHigh]

Finally faster exceptions. I throw exceptions like there is no tomorrow!

[alexandrehtrb]

Please resume posting .NET release news on devblogs 😄

[bgrainger]

Will an api-diff for Preview 3 be published? Preview 2 has one here: https://github.com/dotnet/core/blob/main/release-notes/9.0/preview/preview2/api-diff/README.md but there's nothing currently available for preview3.

[martincostello]

#9273