Uno Platform 6.6 introduces Native AOT publishing across five target platforms, an optional Vulkan rendering backend, and automatic registration for the framework’s Model Context Protocol servers. The release also reduces XAML boilerplate, expands cross-platform WinUI API coverage, and improves accessibility and multilingual text handling.

Uno Platform allows developers to build applications for Windows, WebAssembly, Android, iOS, macOS, and Linux using WinUI-style XAML and .NET. Recent releases have also added visual design and AI-assisted development tooling. Version 6.6 focuses more heavily on runtime performance and filling gaps between WinUI APIs and Uno’s Skia-based targets.

The most significant runtime change is Native AOT support for Android, iOS, Linux, macOS, and Windows. Native AOT compiles application code ahead of time rather than relying on JIT compilation at startup. Uno reported startup improvements ranging from 21% on iOS to 61% on Android in tests using its Chefs sample application on .NET 10, although results will depend on application structure, hardware, and deployment configuration. JIT-based publishing remains supported.

Uno Platform 6.6 also introduces an opt-in Vulkan backend on Windows, Linux, and Android. OpenGL remains the default Skia backend on those platforms, while Apple targets continue using Metal and WebAssembly uses WebGL. According to the Uno team, Vulkan reduced per-frame rendering costs by as much as 50% in some tests, making the option potentially useful for animation-heavy or graphics-intensive applications.

The release simplifies XAML authoring by making the standard WinUI presentation namespace and the x: namespace implicitly available. Developers can also define shared namespaces centrally in a GlobalNamespaces.xaml file. In addition, pages declaring x:Class can now receive generated code-behind classes automatically, allowing XAML-only pages to exist without an otherwise empty .xaml.cs file. Manual code-behind remains available when applications need constructors, event handlers, or lifecycle overrides.

For AI-assisted workflows, Uno’s App MCP and Docs MCP servers can now register themselves with supported development agents. The App MCP exposes a running application to an agent for inspection and interaction, while the Docs MCP provides access to current Uno documentation. Automatic registration is supported for tools including Visual Studio and VS Code Copilot, Claude Code, Cursor, Codex CLI, and Gemini CLI, but not all agents support it yet.

Accessibility support has also expanded for applications rendered through Skia. Screen readers can now access Uno interfaces on Windows, macOS, and WebAssembly. Android and iOS support remains in progress, while Linux support is planned. The release additionally provides complete Input Method Editor composition for multi-keystroke Asian languages across all principal Uno targets and introduces automatic font fallback for interfaces containing multiple writing systems.

Uno Platform 6.6 broadens WinUI compatibility with APIs for projections, geometry transforms, text highlighting, spell checking, flyouts, clipboard operations, drag and drop, and WebView2. Other additions include animated WebP playback and Mica and Acrylic window backdrops on macOS. The exact support level varies by target, so applications relying on these APIs should review the platform-specific notes.

SkiaSharp 4.x is available as an opt-in dependency, while Uno 6.6 continues to use SkiaSharp 3.x by default. Developers upgrading existing applications must update the Uno SDK entry in global.json and consult the migration guide for project-specific changes. Further details, benchmarks, setup instructions, and API coverage notes are available in the Uno Platform announcement, GitHub release notes and documentation.