Last week, Microsoft released .NET 10 Preview 7. This update brings a wide range of improvements across ASP.NET Core, C#, .NET MAUI, and Windows Forms, marking another step toward the final release.
In ASP.NET Core, several notable changes have been introduced. A new configuration option now allows developers to suppress exception handler diagnostics. According to Microsoft, this feature provides flexibility when certain exceptions are already handled and should not be logged at the error level. The default behavior has also been modified so that exceptions resolved by IExceptionHandler no longer produce diagnostics unless explicitly configured.
Cookie authentication has been adjusted to better support APIs. Requests to known API endpoints that lack authentication now return 401 or 403 status codes instead of redirecting to login pages. This aligns with common API practices and can be overridden if needed. Passkey authentication also sees improvements, with new simplified APIs and broader support within Blazor Web App templates, making passwordless sign-in scenarios easier to implement.
ASP.NET Core now fully supports the .localhost top-level domain, enabling developers to run multiple local apps with clearer domain separation. Kestrel, the built-in web server, recognizes .localhost addresses as loopback, ensuring secure and consistent local development. Additionally, support for PipeReader in System.Text.Json has been enabled, offering performance improvements while retaining compatibility.
Blazor received several refinements, including renamed components and APIs for clarity, updated metric names to follow OpenTelemetry conventions, and validation of configured services for WebAssembly apps at build time. OpenAPI.NET integration has been upgraded to the 2.0 stable release, ensuring greater stability for API documentation. Other updates include corrected metadata handling for form data parameters and more reliable merging of XML documentation in OpenAPI generators.
Regarding the C# programming language version 14, Preview 7 has reached feature completeness for version 14. As stated by the dev team in release notes:
Preview 7 represents feature complete for C# 14. Any features available only in later previews will be gated behind feature flags. That enables a longer feedback cycle for any additional features.
.NET MAUI introduces a new XAML source generator, which are as reported designed to improve build performance and IntelliSense support by generating strongly-typed code at compile time. The MediaPicker now handles EXIF data automatically, ensuring correct image orientation. SafeArea support has been enhanced, particularly on iOS, with improved defaults and more precise control. Developers also gain access to secondary toolbar items on iOS and macOS, following modern UI conventions. Several new control APIs were added, and deprecated APIs have been removed as part of ongoing modernization.
On the platform side, .NET for Android includes fixes and updated support for API level 36, while .NET for iOS, Mac Catalyst, macOS, and tvOS now support Xcode 26 Beta 4 for .NET 9 targets. This release also delivers improvements in binding generation, runtime performance, and platform-specific APIs.
Windows Forms has received updates focused on dark mode rendering. Fixes include corrected backgrounds for disabled ComboBox and RichTextBox controls, as well as enhancements to PropertyGrid buttons to ensure consistent UI quality.
As reported, Preview 7 brings the .NET 10 cycle closer to completion, with feature sets for C# 14 and framework updates largely stabilized. For interested readers, full release notes with detailed explanations, code samples, and breaking changes are available on Microsoft’s official documentation.
