.NET 11 Preview 7 Adds Passkeys, Incremental XAML Hot Reload, and Shell Route Templates to MAUI

Passkeys in .NET MAUI Preview 7 integrate native platform authentication via WebAuthn, but the API only handles the client-side ceremony. Server-side logic, challenge generation, assertion validation, and trust configuration, remains the developer’s responsibility. This split means apps must still implement relying-party servers, including Apple’s App Site Association or Android’s Digital Asset Links. The API’s platform support is also version-gated, requiring Android 14+ or iOS 16+, which may limit adoption in apps targeting older devices.

Incremental XAML Hot Reload in Preview 7 replaces the existing full-rebuild approach with a source generator and MetadataUpdateHandler. It handles most XAML changes, property updates, structural reordering, bindings, but developers can revert to the legacy path via EnableMauiIncrementalHotReload. The feature is enabled by default in Debug builds, reducing iteration time, but its preview status suggests edge cases may remain. The same mechanism works with dotnet watch, but physical iOS/tvOS devices now support Hot Reload over USB or Wi-Fi, a workflow improvement for Apple platforms.

Shell route templates in Preview 7 adopt ASP.NET Core’s routing syntax, supporting required, optional, and constrained segments. However, the implementation only allows absolute navigation, not relative paths, which may complicate nested navigation scenarios. Parameter values integrate with existing QueryProperty and IQueryAttributable, but the limitation could force workarounds in apps with complex routing hierarchies. The feature aligns MAUI with Blazor’s routing model but stops short of full parity.

The renderer-to-handler migration continues on Apple platforms, with NavigationPage and TabbedPage now defaulting to handlers on iOS and Mac Catalyst. Compatibility renderers remain available, but apps with custom renderers or deep page-level customizations must test the change. The shift reduces MAUI’s dependency on legacy code but introduces breaking changes for apps relying on renderer-specific behavior. Preview 7 also expands AOT-safe bindings, though some forms like Self and TemplatedParent still use reflection, risking trimming issues in release builds.

Preview 7’s platform-specific updates include Windows single-instance activation, Android’s FastDeploy2, and media gallery integration. Third-party backends gain extension points via OnPlatform and infrastructure contracts, reducing the need for MAUI patches. However, the release’s preview status means production apps should validate these changes before adoption. The SDK is available via the .NET 11 Preview channel, but the lack of corroborating feeds suggests limited real-world testing so far.