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Windows App SDK 2.1.3

Windows App SDK 2.1.3 is the latest stable servicing release on the 2.x line, with new TitleBar drag-region APIs in WinUI, the LoRA API for Phi Silica promoted to the stable surface, a new Copilot+ PC detection API, expanded Windows ML execution-provider support, an ONNX Runtime update, and a batch of reliability fixes.

What's new in WinAppSDK 2.1.3:

  • TitleBar custom drag regions. TitleBar now recursively walks TitleBar.Content and automatically excludes interactive controls from the drag region while keeping empty gaps draggable by default. Three new APIs (TitleBar.IsDragRegion attached property, TitleBar.AutoRefreshDragRegions, and TitleBar.RecomputeDragRegions()) give developers explicit control when the default behavior isn't sufficient. See PR [microsoft/microsoft-ui-xaml#10936](https://github.com/microsoft/microsoft-ui-xaml/issues/10936) and tracking issue [microsoft/microsoft-ui-xaml#10421](https://github.com/microsoft/microsoft-ui-xaml/issues/10421).
  • Phi Silica LoRA API on the stable surface. Developers can now fine-tune the on-device Phi Silica language model with their own LoRA adapters from the stable API surface, using LanguageModelLowRankAdapter.CreateFromPath and LanguageModelOptions.LowRankAdapter. See Phi Silica LoRA for details.
  • AICapabilities.HasAICapability is a new API that lets third-party applications determine whether the device is a Copilot+ PC.
  • Windows ML execution-provider improvements. This release adds support for multiple execution providers within a single MSIX package, discovery of execution providers delivered as framework packages, and a new selection mode for more flexible deployment configurations.
  • The version of ONNX Runtime has been updated to 1.24.6.

Bug fixes:

Bug Fix Runtime Compatibility Change
Fixed a memory leak in ItemsRepeater where recycled elements were never garbage collected due to a reference cycle through the RecyclePool, which could also cause crashes in InvalidateChildrenMeasure. ItemTemplateWrapper_RecyclePoolLeak
Fixed a crash where an implicit Show/Hide animation completion callback could access a destroyed CUIElement, causing an access violation. The callback now uses a weak reference to safely handle the case where the element is destroyed before the animation completes. Animation_FixImplicitHideAnimationCrash
Fixed an issue where windowed popup content opened in a XAML Island did not respect OverrideScale, causing content to appear oversized and clipped. See GitHub issue [microsoft/microsoft-ui-xaml#11000](https://github.com/microsoft/microsoft-ui-xaml/issues/11000). Popup_WindowedPopupOverrideScale
Fixed a fail-fast crash caused by re-entrant dispatch during cross-apartment COM release operations in UIAffinityReleaseQueue::DoCleanup. UIAffinityReleaseQueue_PauseDispatchDuringCleanup
Fixed ambiguous module lookup in WinUI when multiple modules with the same name are loaded in the same process. GetModuleHandleW has been replaced with GetModuleHandleExW so the correct module is resolved by address. GetModuleHandle_FixAmbiguousModuleLookup
Fixed an integer divide-by-zero crash in UniformGridLayout::GetMajorSize when an ItemsRepeater is laid out in an available width narrower than one item's minor stride. UniformGridLayout_GetItemsPerLineDivideByZero
Fixed a potential crash when a package has been uninstalled prior to being processed. PackageManager_FixCrash
Fixed an issue where GetReadyState could return incorrect error codes (for example, DisabledByUser or NotSupportedOnCurrentSystem) when required packages were not yet deployed. The API now correctly reports NotReady in this scenario, improving diagnostic clarity. ModelInitialization_GetReadyStateAvailabilityGuard
Fixed an issue where XAML compiler errors were silently lost when using dotnet build, showing only MSB3073: exited with code 1 instead of the actual error messages. See GitHub issue [microsoft/microsoft-ui-xaml#9813](https://github.com/microsoft/microsoft-ui-xaml/issues/9813). N/A, build-time XAML compiler tooling change

To see everything that's new and changed, see the full Windows App SDK 2.1.3 release notes.

Try it out

  • Download the 2.1.3 NuGet package to use WinAppSDK 2.1 in your app.
  • Download and update the WinUI Gallery to see the WinUI 3 updates firsthand.

Getting started

To get started using Windows App SDK to develop Windows apps, check out the following documentation:

Source: README.md, updated 2026-05-18