Table of Contents

• Libraries
• Runtime
• C#
• SDK
• ASP.NET Core
• .NET MAUI
• Get Started
• Team Announcements & Discussions
• Stay up-to-date with .NET 9

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Libraries

• Removal of is complete
• Enumerate over segments now reports assert condition, by default
• Compression APIs now use enables creating GUIDs with a natural sort order for more types
• AES-GCM and ChaChaPoly1305 algorithms enabled for iOS/tvOS/MacCatalyst
• Changes to X.509 Certificate Loading
• Support for XPS documents from XPS virtual printer

Runtime

• ARM64 SVE Support
• Post-Indexed Addressing on ARM64
• Strength Reduction in Loops
• Object Stack Allocation for Boxes
• GC Dynamic Adaptation To Application Sizes

C#

• Prioritize better overloads with attribute

SDK

• Container publishing improvements for insecure registries
• More consistent environment variables for container publishing
• Introduction of Workload Sets for more control over workloads
• Mitigating analyzer mismatch issues aka ‘torn SDK’

ASP.NET Core

• SignalR supports trimming and Native AOT
• Microsoft.AspNetCore.OpenApi supports trimming and Native AOT
• Improvements to transformer registration APIs in Microsoft.AspNetCore.OpenApi
• Call and on route groups
• Construct and result types with values support for Pushed Authorization Requests (PAR)
• Data Protection support for deleting keys
• Customize Kestrel named pipe endpoints
• Improved Kestrel connection metrics
• Opt-out of HTTP metrics on certain endpoints and requests option to choose the status code based on the exception

.NET MAUI

• Introduction of New Control and for Windows & improvements with a new opt-in handler for iOS and Mac Catalyst
• Ability to bring a to the foreground with binding mode backward compatibility host address
• Native Embedding improvements is Obsolete
• New Handler Disconnect Policy
• New event on Control
• New lifecycle methods for remote notifications on iOS & Mac Catalyst
• Xcode Sync for CLI and Visual Studio Code

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.
• .NET 9 can now be installed directly through the Visual Studio installer starting with Visual Studio 2022 17.12 Preview 1.
• You can also use Visual Studio Code and the C# Dev Kit extension with .NET 9.

Team Announcements & Discussions

• The team has been making monthly announcements alongside full release notes on the dotnet/core GitHub Discussions and has seen great engagement and feedback from the community.
• .NET Conf 2024 is scheduled for November alongside the launch of .NET 9. Save the date!

Stay up-to-date with .NET 9

• 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
• Subscribe to the GitHub Discussions RSS news feed for all release announcements.
• Join the .NET 9 Preview 7 GitHub Discussion to discuss features and provide feedback for this release.