Windows 10 SDK - Windows app development

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.

System requirements

The Windows SDK has the following minimum system requirements:

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.

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

Previous SDK versions

Release notes & Known Issues