What’s cool in Windows 10

Whether you build with or for Windows, enhance your apps with the new features in the Windows 10 May 2020 Update.

WinUI 2.4

The latest official release of the Windows UI Library – WinUI 2.4 – provides new XAML controls to aid the intuitive display of information in your Windows app. WinUI APIs run on earlier versions of Windows 10, so you don’t have to include version checks or conditional XAML to supports users who aren’t on the latest OS.

RadialGradientBrush

The RadialGradientBrush lets you create an ellipse, with a color gradient originating at the center and ending at a specified X and Y radius.

ProgressRing

The ProgressRing control can indicate that users are blocked from interacting with your app until an operation completes.

XAML Controls Gallery

The XAML Controls Gallery app lets you get a hands-on preview with every WinUI control, including those new in WinUI 2.4.

Windows Subsystem for Linux

Windows Subsystem for Linux 2 (WSL 2) is a new version of WSL, which features significantly faster file IO performance and full system call capability.

Install WSL 2

Want to get started? Follow these steps to install WSL 2 on your computer.

New in WSL 2

Learn more about the new features in WSL 2, and how its changes affect your workflow.

Docker in WSL

Docker is now supported on WSL 2. Learn how to install the preview, and integrate it with VS Code.

Windows AI

Integrate machine learning models into your apps with Windows ML. Use automatic code generation and new APIs for hardware accelerated, local evaluation of trained models on your Windows 10 devices. Among other updates, Windows ML now supports ONNX version 1.4 (opset 9).

MSIX and the Application Model

MSIX is the Windows app package format that provides a modern packaging experience to all Windows apps. The open-source MSIX format preserves the functionality of existing packages, while enabling modern packaging and deployment features.

Packaging with Services

MSIX and the MSIX Packaging Tool now support app packages that contain services.

Sparse Packages

If your app isn’t packaged with MSIX, you can now enable it to use Windows features that require a package identity.

Hosted Apps

You can now create Hosted Apps, which share the same executable and definition as a parent app, but behave like a separate app.

XAML Islands

XAML Islands allows you to host UWP controls in your Windows Desktop applications. Using new NuGet packages, it’s now possible to even host custom UWP controls in your WPF, Windows Forms, or C++ Win32 applications.

.NET Standard 2.0

Share more code between UWP, Android, iOS, ASP.NET, Windows Forms, and WPF applications by using .NET Standard 2.0 class libraries.

Visual Studio 2019

Visual Studio 2019 makes it easier than ever to start a new project, and debug your existing apps. Code faster. Work smarter. Create the future.

Mixed Reality

Build apps for immersive headsets that merge the physical and virtual worlds.

Stay up to date

See what’s coming in the future of Windows 10 with the Windows Insider Program

Windows 10 SDK

The Windows 10 SDK (10.0.19041.0) for Windows 10, version 2004 provides the latest headers, libraries, metadata, and tools for building Windows 10 apps.

Use this SDK to build Universal Windows Platform (UWP) and Win32 applications for Windows 10, version 20H2 and previous Windows releases.

Windows 10, version 20H2 is a scoped set of features for select performance improvements and quality enhancements. Developers should be aware of this release, but no action is necessary at this time.

A new Windows SDK will not be issued to accompany this version of Windows because this release doesn’t introduce new APIs. That means there’s no need to modify your project files or target a new version of Windows, and you should continue to use the Windows 10 SDK for Windows 10, version 2004. When setting the target version for your Windows app, Windows 10 build 19041 is still the most recent target version.

Getting started

You can get the Windows 10 SDK in two ways: install it from this page by selecting the download link or by selecting “Windows 10 SDK (10.0.19041.0)” in the optional components of the Visual Studio 2019 Installer.

Before you install this SDK:

System requirements

The Windows SDK has the following minimum system requirements:

Supported operating systems

• Universal Windows Platform (UWP) app development
  • Windows 10 version 1507 or higher: Home, Professional, Education, and Enterprise (LTSB and S are not supported)
  • Windows Server 2019, Windows Server 2016 and Windows Server 2012 R2 (Command line only)

• Win32 app development
  • Windows 10 version 1507 or higher
  • Windows Server 2019, Windows Server 2016, and Windows Server 2012 R2 (Command line only)
  • Windows 8.1
  • Windows 7 SP1

(Not all tools are supported on earlier operating systems)

Hardware requirements

• 1.6 GHz or faster processor
• 1 GB of RAM
• 4 GB of available hard disk space

Additional SDK requirements

Installation on Windows 8.1 and earlier operating systems requires KB2999226. To install through Windows Update, make sure you install the latest recommended updates and patches from Microsoft Update before you install the Windows SDK.

What’s new

The Windows 10 SDK for Windows 10, version 2004 offers exciting new APIs and updated tools for developing your Windows applications. Learn more about the new features in Windows 10, version 2004.

To see the new APIs introduced with Windows 10, version 2004, see: What’s new in Windows 10 for developers, build 19041.

Removal of api-ms-win-net-isolation-l1-1-0.lib

In this release api-ms-win-net-isolation-l1-1-0.lib has been removed from the Windows SDK. Apps that were linking against api-ms-win-net-isolation-l1-1-0.lib can switch t OneCoreUAP.lib as a replacement.

Removal of irprops.lib

In this release irprops.lib has been removed from the Windows SDK. Apps that were linking against irprops.lib can switch to bthprops.lib as a drop-in replacement.

Removal of wuapicommon.h and wuapicommon.idl

In this release we have moved ENUM tagServerSelection from wuapicommon.h to wupai.h and removed the header. If you would like to use the ENUM tagServerSelection, you will need to include wuapi.h or wuapi.idl.

Windows 10 WinRT API Pack

The Windows 10 WinRT API Pack lets you add the latest Windows Runtime APIs support to your .NET Framework 4.5+ and .NET Core 3.0+ libraries and apps. To access the Windows 10 WinRT API Pack, see the Microsoft.Windows.SDK.Contracts nuget package.

Universal C Runtime (UCRT)

The printf family of functions now conforms with the IEEE 754 rounding rules when printing exactly representable floating-point numbers and will honor the rounding mode requested via calls to fesetround. Legacy behavior is available when linking with legacy_stdio_float_rounding.obj.

Tools

Windows App Certification Kit

In this release of the Windows SDK, several new APIs were added to the Supported APIs list in the App Certification Kit and Windows Store. If there are APIs in the supported list that appear greyed out or disabled in Visual Studio, you can make a small change to your source file, to access them. For more details, see this known issue.

In addition to adding APIs, the following changes have been made to the tests:

Updated tests:

• ValidateContentUriRules will be informational only. Test failures will be presented as warnings.

Removed tests

• WebView WinRT access test for web app
• PackageSizeCheck test for UWP apps
• SupportedApi test for Desktop Bridge apps
• AppContainerCheck test from BinScope for UWP apps
• ServiceWorker check for all app types

New tests

• High-DPI test. A new test for Desktop Bridge apps checks if the app uses DPI aware feature and warns if not specified. This test will encourage you to make your app per-monitor DPI aware. For details on DPI see High DPI Desktop Application Development on Windows.

Message Compiler (mc.exe)

Updates include:

• Now detects the Unicode byte order mark (BOM) in .mc files. If the .mc file starts with a UTF-8 BOM, it will be read as a UTF-8 file. Otherwise, if it starts with a UTF-16LE BOM, it will be read as a UTF-16LE file. If the -u parameter was specified, it will be read as a UTF-16LE file. Otherwise, it will be read using the current code page (CP_ACP).
• Now avoids one-definition-rule (ODR) problems in MC-generated C/C++ ETW helpers caused by conflicting configuration macros (e.g. when two .cpp files with conflicting definitions of MCGEN_EVENTWRITETRANSFER are linked into the same binary, the MC-generated ETW helpers will now respect the definition of MCGEN_EVENTWRITETRANSFER in each .cpp file instead of arbitrarily picking one or the other).

Windows Trace Preprocessor (tracewpp.exe)

Updates include:

• Now supports Unicode input (.ini, .tpl, and source code) files. Input files starting with a UTF-8 or UTF-16 byte order mark (BOM) will be read as Unicode. Input files that do not start with a BOM will be read using the current code page (CP_ACP). For backwards-compatibility, if the -UnicodeIgnore command-line parameter is specified, files starting with a UTF-16 BOM will be treated as empty.
• Now supports Unicode output (.tmh) files. By default, output files will be encoded using the current code page (CP_ACP). Use command-line parameters -cp:UTF-8 or -cp:UTF-16 to generate Unicode output files.
• Behavior change: tracewpp now converts all input text to Unicode, performs processing in Unicode, and converts output text to the specified output encoding. Earlier versions of tracewpp avoided Unicode conversions and performed text processing assuming a single-byte character set. This may lead to behavior changes in cases where the input files do not conform to the current code page. In cases where this is a problem, consider converting the input files to UTF-8 (with BOM) and/or using the -cp:UTF-8 command-line parameter to avoid encoding ambiguity.

TraceLoggingProvider.h

Updates include:

• Now avoids one-definition-rule (ODR) problems caused by conflicting configuration macros (e.g. when two .cpp files with conflicting definitions of TLG_EVENT_WRITE_TRANSFER are linked into the same binary, the TraceLoggingProvider.h helpers will now respect the definition of TLG_EVENT_WRITE_TRANSFER in each .cpp file instead of arbitrarily picking one or the other).
• In C++ code, the TraceLoggingWrite macro has been updated to enable better code sharing between similar events using variadic templates.

Signing your apps with Device Guard Signing

We are making it easier for you to sign your app. Device Guard signing is a Device Guard feature that is available in Microsoft Store for Business and Education. Signing allows enterprises to guarantee every app comes from a trusted source. Our goal is to make signing your MSIX package easier. See the documentation about Device Guard Signing.

Samples

Windows 10 app samples are now available through GitHub. You can browse the code on GitHub, clone a personal copy of the repository from Git, or download a zipped archive of all the samples. We welcome feedback, so feel free to open an issue within the repository if you have a problem or question. These samples are designed to run on desktop, mobile, and future devices that support the Universal Windows Platform (UWP).

Previous SDK versions

Previously released SDKs and emulators, including update details, can be found on the archive page.

API Light Up

When you use new APIs, consider writing your app to be adaptive so that it runs correctly on the widest array of Windows 10 devices. An adapative app «lights up» with new features wherever the devices and Windows version supports them, but otherwise offers only the functionality available on the detected platform version. For implementation details, see the Version adaptive code article.

Release notes & Known Issues

The Windows 10 SDK, Version 2004 SDK servicing update (released 12/16/2020) contains the following fixes. If you encounter these issues, we recommend that you update your version of the SDK as soon as possible to avoid them:

• Resolved unpredictable and hard to diagnose crashes when linking both umbrella libraries and native OS libraries (for example, onecoreuap.lib and kernel32.lib)
• Resolved issue that prevented AppVerifier from working
• Resolved issue that caused WACK to fail with “Task failed to enable HighVersionLie”

For known issues, see the winapi-sdk Q&A.

For new developer feature requests, submit through the Feedback Hub app under the category “Developer Platform/API.”

More resources

Downloads and tools

Get the latest editions of Visual Studio and Windows 10 development tools.

SDK archive

Find previous releases of the Window SDK and other tools.

Windows blog

Stay in touch with the latest SDK flights by subscribing to our blog.

Windows lifecycle fact sheet

Find the key dates for Windows release updates and end of support.