From 1fa8f16ed10f2a212b67cc0f088ca37c49f81d8b Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 9 Jul 2025 12:54:11 -0700
Subject: [PATCH 01/32] Support '1.' TFM for CsWinRT 3.0

---
 eng/ManualVersions.props                        | 11 +++++++++++
 .../targets/GenerateBundledVersions.targets     | 17 +++++++++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/eng/ManualVersions.props b/eng/ManualVersions.props
index 9b67e035d26a..9738c1935cc5 100644
--- a/eng/ManualVersions.props
+++ b/eng/ManualVersions.props
@@ -9,6 +9,17 @@
   Basically: In this file, choose the highest version when resolving merge conflicts.
  -->
   <PropertyGroup>
+
+    <!-- CsWinRT 3.0 targeting packs -->
+    <MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion>10.0.17763.57</MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion>10.0.18362.57</MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion>10.0.19041.57</MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion>10.0.20348.57</MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion>10.0.22000.57</MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion>10.0.22621.57</MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion>
+    <MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion>10.0.26100.57</MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion>
+
+    <!-- CsWinRT 2.x targeting packs-->
     <MicrosoftWindowsSDKNETRef10_0_17763PackageVersion>10.0.17763.57</MicrosoftWindowsSDKNETRef10_0_17763PackageVersion>
     <MicrosoftWindowsSDKNETRef10_0_18362PackageVersion>10.0.18362.57</MicrosoftWindowsSDKNETRef10_0_18362PackageVersion>
     <MicrosoftWindowsSDKNETRef10_0_19041PackageVersion>10.0.19041.57</MicrosoftWindowsSDKNETRef10_0_19041PackageVersion>
diff --git a/src/Layout/redist/targets/GenerateBundledVersions.targets b/src/Layout/redist/targets/GenerateBundledVersions.targets
index 9237525dec17..7f5318cd01b3 100644
--- a/src/Layout/redist/targets/GenerateBundledVersions.targets
+++ b/src/Layout/redist/targets/GenerateBundledVersions.targets
@@ -1316,8 +1316,21 @@ Copyright (c) .NET Foundation. All rights reserved.
                               TargetingPackName="NETStandard.Library.Ref"
                               TargetingPackVersion="$(NETStandardLibraryRefPackageVersion)"
                               />
-
-    <!-- Supported Windows versions -->
+    
+    <!--
+      Supported Windows versions using CsWinRT 3.0 (.NET 10 is the baseline). This leverages the patch version of
+      the Windows SDK version to allow multi-targeting, which is required to allow customers to gradually migrate.
+      Both CsWinRT 3.0 and 2.x will be supported for a period of time, and packages can target both of them.
+    -->
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.20348.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.19041.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.18362.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.17763.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion)" MinimumNETVersion="10.0" />
+
+    <!-- Supported Windows versions using CsWinRT 2.x -->
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000PackageVersion)" MinimumNETVersion="8.0" />

From 2ad93023b4fc96865bdd9fe3d732ceaba87501c0 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 9 Jul 2025 13:37:50 -0700
Subject: [PATCH 02/32] Add 'UsingPreviewCsWinRT3_0Feature' warning

---
 src/Tasks/Common/Resources/Strings.resx              |  7 +++++--
 src/Tasks/Common/Resources/xlf/Strings.cs.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.de.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.es.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.fr.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.it.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.ja.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.ko.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.pl.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf     |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.ru.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.tr.xlf        |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf   |  5 +++++
 src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf   |  5 +++++
 .../targets/Microsoft.NET.Windows.targets            | 12 ++++++++++++
 15 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/src/Tasks/Common/Resources/Strings.resx b/src/Tasks/Common/Resources/Strings.resx
index 46d7589727a5..bbebadd53f08 100644
--- a/src/Tasks/Common/Resources/Strings.resx
+++ b/src/Tasks/Common/Resources/Strings.resx
@@ -875,7 +875,6 @@ You may need to build the project on another operating system or architecture, o
   <data name="SolutionProjectConfigurationsConflict" xml:space="preserve">
     <value>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</value>
-  <comment>{StrBegins="NETSDK1197: "}</comment>
   </data>
   <data name="PublishProfileNotPresent" xml:space="preserve">
     <value>NETSDK1198: A publish profile with the name '{0}' was not found in the project. Set the PublishProfile property to a valid file name.</value>
@@ -995,4 +994,8 @@ You may need to build the project on another operating system or architecture, o
     <value>NETSDK1228: This project depends on the Aspire Workload which has been deprecated. Aspire now ships via NuGet packages and no longer requires a workload. Please visit {0} for upgrade guidance.</value>
     <comment>{StrBegins="NETSDK1228: "}</comment>
   </data>
-</root>
+  <data name="UsingPreviewCsWinRT3_0Feature" xml:space="preserve">
+    <value>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</value>
+    <comment>{StrBegins="NETSDK1229: "}</comment>
+  </data>
+</root>
\ No newline at end of file
diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
index e5db44587134..79b3b0cada71 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: K sestavování desktopových aplikací pro Windows se vyžaduje Microsoft.NET.Sdk.WindowsDesktop. Aktuální verze sady SDK nepodporuje hodnoty UseWpf a UseWindowsForms.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Používáte verzi Preview rozhraní .NET. Viz: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
index c246782b9f1c..589eedc07a2a 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.de.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Für das Erstellen von Windows-Desktopanwendungen ist Microsoft.NET.Sdk.WindowsDesktop erforderlich. "UseWpf" und "UseWindowsForms" werden vom aktuellen SDK nicht unterstützt.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Sie verwenden eine Vorschauversion von .NET. Weitere Informationen: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
index 0bf7f4613d62..0a14687ca819 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.es.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Se requiere Microsoft.NET.Sdk.WindowsDesktop para compilar las aplicaciones de escritorio de Windows. El SDK actual no admite "UseWpf" ni "UseWindowsForms".</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Está usando una versión preliminar de .NET. Visite: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
index d3f640ff0d76..7661d5070311 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: vous devez disposer de Microsoft.NET.Sdk.WindowsDesktop pour générer des applications de bureau Windows. 'UseWpf' et 'UseWindowsForms' ne sont pas pris en charge par le kit SDK actuel.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: vous utilisez une version d'aperçu de .NET. Voir : https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
index 6ac472c5fc66..96f5b2ab7974 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.it.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: per compilare applicazioni desktop di Windows, è necessario Microsoft.NET.Sdk.WindowsDesktop. 'UseWpf' e 'UseWindowsForms' non sono supportati dall'SDK corrente.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: si sta usando una versione in anteprima di .NET. Vedere https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
index bb47aae43458..89481a1d9ff5 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Windows デスクトップ アプリケーションを作成するには、Microsoft.NET.Sdk.WindowsDesktop が必要です。現在の SDK では、'UseWpf' と 'UseWindowsForms' はサポートされていません。</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: プレビュー版の .NET を使用しています。https://aka.ms/dotnet-support-policy をご覧ください</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
index b73e728c7177..45b18dbc015f 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Microsoft.NET.Sdk.WindowsDesktop을 사용하려면 Windows 데스크톱 애플리케이션을 빌드해야 합니다. 'UseWpf' 및 'UseWindowsForms'는 현재 SDK에서 지원하지 않습니다.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: .NET의 미리 보기 버전을 사용하고 있습니다. 참조: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
index 2ab598421867..83a2569fb663 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Do kompilowania aplikacji klasycznych systemu Windows konieczny jest zestaw Microsoft.NET.Sdk.WindowsDesktop. Właściwości „UseWpf” i „UseWindowsForms” nie są obsługiwane przez bieżący zestaw SDK.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Korzystasz z wersji zapoznawczej platformy .NET. Zobacz: ttps://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
index 1932439c9340..cd0cf0b24a20 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Microsoft.NET.Sdk.WindowsDesktop é necessário para compilar aplicativos da área de trabalho do Windows. Não há suporte para 'UseWpf' e 'UseWindowsForms' no SDK atual.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Você está usando uma versão de visualização do .NET. Veja: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
index f8a1ae31c21f..b5aa4f4aca7b 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: для сборки классических приложений для Windows требуется Microsoft.NET.Sdk.WindowsDesktop. "UseWpf" и "UseWindowsForms" не поддерживаются текущим пакетом SDK.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Вы используете предварительную версию .NET. Дополнительные сведения см. на странице https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
index 9e0915877476..966edca2f615 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: Windows Masaüstü uygulamalarını derlemek için Microsoft.NET.Sdk.WindowsDesktop gereklidir. 'UseWpf' ve 'UseWindowsForms' geçerli SDK tarafından desteklenmiyor.</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: Bir .NET önizleme sürümü kullanıyorsunuz. Bkz. https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
index 1b093b67114d..ba33dd01d3cf 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: 要构建 Windows 桌面应用程序，需使用 Microsoft.NET.Sdk.WindowsDesktop。当前 SDK 不支持 "UseWpf" 和 "UseWindowsForms"。</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: 你正在使用 .NET 的预览版。请参阅 https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
index a22286f247f4..aa8e45f67284 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
@@ -1043,6 +1043,11 @@ The following are names of parameters or literal values and should not be transl
         <target state="translated">NETSDK1107: 需有 Microsoft.NET.Sdk.WindowsDesktop 才能建置 Windows 傳統型應用程式。目前的 SDK 不支援 'UseWpf' 和 'UseWindowsForms'。</target>
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
+      <trans-unit id="UsingPreviewCsWinRT3_0Feature">
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <note>{StrBegins="NETSDK1229: "}</note>
+      </trans-unit>
       <trans-unit id="UsingPreviewSdk">
         <source>NETSDK1057: You are using a preview version of .NET. See: https://aka.ms/dotnet-support-policy</source>
         <target state="translated">NETSDK1057: 您目前使用的是 .NET 預覽版。請參閱: https://aka.ms/dotnet-support-policy</target>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index 644d0faa4658..2c126237bfa6 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -167,4 +167,16 @@ Copyright (c) .NET Foundation. All rights reserved.
                       and '$(UseUwp)' == 'true' ">
     <NetSdkError ResourceName="WindowsSDKXamlInvalidTfm" />
   </Target>
+
+  <!--
+    Emit a warning if using CsWinRT 3.0, which is selected when targeting a Windows SDK with '1' as the patch version.
+    NOTE: remove this target when CsWinRT 3.0 is released as a stable version and becomes officially supported.
+  -->
+  <Target Name="_WarnForCsWinRT3_0PreviewFeatureEnabled"
+          AfterTargets="ResolvePackageAssets"
+            Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true'
+                        and $([System.Version]::Parse('$(TargetPlatformVersion)').Build) == 1">
+    <NETSdkWarning ResourceName="UsingPreviewCsWinRT3_0Feature"
+                   FormatArguments="$(TargetPlatformVersion)" />
+  </Target>
 </Project>

From c25600600fbc705eb7171ab68f62c8889c7c8ac5 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 9 Jul 2025 13:39:28 -0700
Subject: [PATCH 03/32] Add test for new preview warning

---
 ...ThatWeWantToBuildAWindowsDesktopProject.cs | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 9f2d59cbab70..d8c129cf4e5a 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -478,6 +478,26 @@ public void ItDoesNotWarnAnymoreWhenBuildingAProjectWithUseUwpProperty()
                 .NotHaveStdOutContaining("NETSDK1219");
         }
 
+        [WindowsOnlyFact]
+        public void ItWarnsWhenBuildingAProjectTargetingCsWinRT3_0()
+        {
+            TestProject testProject = new()
+            {
+                Name = "A",
+                ProjectSdk = "Microsoft.NET.Sdk",
+                TargetFrameworks = "net10.0-windows10.0.22621.1"
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass()
+                .And
+                .NotHaveStdOutContaining("NETSDK1229");
+        }
+
         [WindowsOnlyFact]
         public void ItErrorsWhenTargetingBelowNet6WithUseUwpProperty()
         {

From 4821072e6f4eefc4558c146b3efa1c35b869797a Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 9 Jul 2025 13:56:54 -0700
Subject: [PATCH 04/32] Run 'msbuild /t:UpdateXlf'

---
 src/Tasks/Common/Resources/xlf/Strings.cs.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.de.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.es.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.fr.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.it.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ja.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ko.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.pl.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf   | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ru.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.tr.xlf      | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf | 4 ++--
 13 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
index 79b3b0cada71..4e5b591459c8 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Projekt(y) několika řešení obsahuj(e/í) konfliktní hodnoty „{0}“; ujistěte se, že se hodnoty shodují. Zvažte použití souboru Directory.build.props k nastavení vlastnosti pro všechny projekty. Konfliktní projekty:
+        <target state="needs-review-translation">NETSDK1197: Projekt(y) několika řešení obsahuj(e/í) konfliktní hodnoty „{0}“; ujistěte se, že se hodnoty shodují. Zvažte použití souboru Directory.build.props k nastavení vlastnosti pro všechny projekty. Konfliktní projekty:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
index 589eedc07a2a..90c80bb7a38a 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.de.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Mehrere Projektmappenprojekte enthalten widersprüchliche Werte für "{0}". Stellen Sie sicher, dass die Werte übereinstimmen. Erwägen Sie die Verwendung einer Directory.build.props-Datei, um die Eigenschaft für alle Projekte festzulegen. In Konflikt stehende Projekte: 
+        <target state="needs-review-translation">NETSDK1197: Mehrere Projektmappenprojekte enthalten widersprüchliche Werte für "{0}". Stellen Sie sicher, dass die Werte übereinstimmen. Erwägen Sie die Verwendung einer Directory.build.props-Datei, um die Eigenschaft für alle Projekte festzulegen. In Konflikt stehende Projekte: 
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
index 0a14687ca819..20107e912a1a 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.es.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Varios proyectos de solución que contienen valores '{0}' en conflicto; asegúrese de que los valores coinciden. Considere la posibilidad de usar un archivo Directory.build.props para establecer la propiedad para todos los proyectos. Proyectos en conflicto:
+        <target state="needs-review-translation">NETSDK1197: Varios proyectos de solución que contienen valores '{0}' en conflicto; asegúrese de que los valores coinciden. Considere la posibilidad de usar un archivo Directory.build.props para establecer la propiedad para todos los proyectos. Proyectos en conflicto:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
index 7661d5070311..ee09bd071ee5 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: plusieurs projets de solution contiennent des valeurs '{0}' en conflit ; assurez-vous que les valeurs correspondent. Envisagez d'utiliser un fichier Directory.build.props pour définir la propriété pour tous les projets. Projets conflictuels : 
+        <target state="needs-review-translation">NETSDK1197: plusieurs projets de solution contiennent des valeurs '{0}' en conflit ; assurez-vous que les valeurs correspondent. Envisagez d'utiliser un fichier Directory.build.props pour définir la propriété pour tous les projets. Projets conflictuels : 
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
index 96f5b2ab7974..d161406ddd1d 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.it.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: più progetti della soluzione contengono valori '{0}' in conflitto. Verificare che i valori corrispondano. Provare a usare un file Directory.build.props per impostare la proprietà di tutti i progetti. Progetti in conflitto:
+        <target state="needs-review-translation">NETSDK1197: più progetti della soluzione contengono valori '{0}' in conflitto. Verificare che i valori corrispondano. Provare a usare un file Directory.build.props per impostare la proprietà di tutti i progetti. Progetti in conflitto:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
index 89481a1d9ff5..3c93be7a54ce 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: 複数のソリューションのプロジェクトに、競合する '{0}' 値が含まれています。値が一致するようにしてください。Directory.build.props ファイルを使用して、すべてのプロジェクトのプロパティを設定することを検討してください。競合するプロジェクト: 
+        <target state="needs-review-translation">NETSDK1197: 複数のソリューションのプロジェクトに、競合する '{0}' 値が含まれています。値が一致するようにしてください。Directory.build.props ファイルを使用して、すべてのプロジェクトのプロパティを設定することを検討してください。競合するプロジェクト: 
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
index 45b18dbc015f..8a5420710946 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: 여러 솔루션 프로젝트에 충돌하는 '{0}' 값이 있습니다. 값이 일치하는지 확인하세요. Directory.build.props 파일을 사용하여 모든 프로젝트에 대한 속성을 설정하는 것이 좋습니다. 충돌하는 프로젝트:
+        <target state="needs-review-translation">NETSDK1197: 여러 솔루션 프로젝트에 충돌하는 '{0}' 값이 있습니다. 값이 일치하는지 확인하세요. Directory.build.props 파일을 사용하여 모든 프로젝트에 대한 속성을 설정하는 것이 좋습니다. 충돌하는 프로젝트:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
index 83a2569fb663..3032f4c2e863 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Wiele projektów rozwiązań zawiera wartości „{0}” powodujące konflikt; upewnij się, że wartości są zgodne. Rozważ użycie pliku Directory.build.props na potrzeby ustawienia właściwości dla wszystkich projektów. Projekty powodujące konflikt:
+        <target state="needs-review-translation">NETSDK1197: Wiele projektów rozwiązań zawiera wartości „{0}” powodujące konflikt; upewnij się, że wartości są zgodne. Rozważ użycie pliku Directory.build.props na potrzeby ustawienia właściwości dla wszystkich projektów. Projekty powodujące konflikt:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
index cd0cf0b24a20..80d63e09ccdf 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Vários projetos de solução contêm valores '{0}' conflitantes; garantir que os valores correspondam. Considere usar um arquivo Directory.build.props para configurar a propriedade para todos os projetos. Projetos conflitantes:
+        <target state="needs-review-translation">NETSDK1197: Vários projetos de solução contêm valores '{0}' conflitantes; garantir que os valores correspondam. Considere usar um arquivo Directory.build.props para configurar a propriedade para todos os projetos. Projetos conflitantes:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
index b5aa4f4aca7b..5c99f99a2821 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: несколько проектов решения содержат конфликтующие значения "{0}". Убедитесь, что значения совпадают. Рассмотрите возможность использования файла Directory.build.props для настройки свойства для всех проектов. Конфликтующие проекты:
+        <target state="needs-review-translation">NETSDK1197: несколько проектов решения содержат конфликтующие значения "{0}". Убедитесь, что значения совпадают. Рассмотрите возможность использования файла Directory.build.props для настройки свойства для всех проектов. Конфликтующие проекты:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
index 966edca2f615..797e7819f3d4 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: Birden çok çözüm projesi çakışan '{0}' değerleri içeriyor; değerlerin eşleştiğinden emin olun. Özelliği tüm projeler için ayarlamak için Directory.build.props dosyası kullanabilirsiniz. Çakışan projeler:
+        <target state="needs-review-translation">NETSDK1197: Birden çok çözüm projesi çakışan '{0}' değerleri içeriyor; değerlerin eşleştiğinden emin olun. Özelliği tüm projeler için ayarlamak için Directory.build.props dosyası kullanabilirsiniz. Çakışan projeler:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
index ba33dd01d3cf..bc3a782cdc6b 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: 多个解决方案项目包含存在冲突的“{0}”值；请确保值能够匹配。请考虑使用 Directory.build.props 文件设置所有项目的属性。存在冲突的项目:
+        <target state="needs-review-translation">NETSDK1197: 多个解决方案项目包含存在冲突的“{0}”值；请确保值能够匹配。请考虑使用 Directory.build.props 文件设置所有项目的属性。存在冲突的项目:
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
index aa8e45f67284..1c79bd08a394 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
@@ -904,9 +904,9 @@ The following are names of parameters or literal values and should not be transl
       <trans-unit id="SolutionProjectConfigurationsConflict">
         <source>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</source>
-        <target state="translated">NETSDK1197: 多個解決方案專案包含衝突的 '{0}' 值; 請確保值相符。考慮使用 Directory.build.props 檔案來設定所有專案的屬性。衝突的專案: 
+        <target state="needs-review-translation">NETSDK1197: 多個解決方案專案包含衝突的 '{0}' 值; 請確保值相符。考慮使用 Directory.build.props 檔案來設定所有專案的屬性。衝突的專案: 
 {1}</target>
-        <note>{StrBegins="NETSDK1197: "}</note>
+        <note />
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>

From aa2210ea742f380bf4f5ef9d779ce2758e7ffbf5 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 15 Jul 2025 09:35:46 -0700
Subject: [PATCH 05/32] Update 'TargetPlatformVersion' parsing

---
 .../Microsoft.NET.TargetFrameworkInference.targets    | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 07e579f5f38e..c4c940e378bf 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -65,6 +65,17 @@ Copyright (c) .NET Foundation. All rights reserved.
   <PropertyGroup Condition="'$(TargetFramework)' != '' and ('$(TargetPlatformIdentifier)' == '' or '$(TargetPlatformVersion)' == '')">
     <TargetPlatformIdentifier Condition="'$(TargetPlatformIdentifier)' == ''">$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)'))</TargetPlatformIdentifier>
     <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 4))</TargetPlatformVersion>
+
+    <!--
+      In order to support multi-targeting between CsWinRT 2.x and CsWinRT 3.0, we use the revision number of the Windows SDK to indicate the CsWinRT version.
+      Specifically, '.0' indicates CsWinRT 2.x, and '.1' indicates CsWinRT 3.0. Because we want the rest of the tooling to still always see the '.0' version
+      for the Windows SDK (as the '.1' only has meaning for the .NET SDK), here we check if we're using CsWinRT 3.0, and if so we store that result and then
+      immediately reset the revision number back to '.0' so that the rest of the tooling continues to see the same version as before.
+    -->
+    <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
+    <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
+    <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 3)).0</TargetPlatformVersion>
+
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
     <!-- Normalize casing of windows to Windows -->

From ba90d36f198c58f0571c6ca44b89b2124cc6b7c2 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 15 Jul 2025 11:14:30 -0700
Subject: [PATCH 06/32] Update targeting pack selection logic

---
 .../CreateWindowsSdkKnownFrameworkReferences.cs | 17 +++++++++++++++++
 ...NET.Sdk.FrameworkReferenceResolution.targets |  1 +
 2 files changed, 18 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index 17138555aed9..0035cba55652 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -17,6 +17,8 @@ public class CreateWindowsSdkKnownFrameworkReferences : TaskBase
     {
         public bool UseWindowsSDKPreview { get; set; }
 
+        public bool UseCsWinRT3 { get; set; }
+
         public string WindowsSdkPackageVersion { get; set; }
 
         public string TargetFrameworkIdentifier { get; set; }
@@ -76,6 +78,21 @@ protected override void ExecuteCore()
                             continue;
                         }
 
+                        // If we're using CsWinRT 3.0, filter to only items with '1' as the revision number.
+                        // Otherwise, if we're using CsWinRT 2.0, exclude all of them and pick '0' revisions.
+                        if ((UseCsWinRT3 && windowsSdkVersionParsed.Revision == 0) ||
+                            (!UseCsWinRT3 && windowsSdkVersionParsed.Revision == 1))
+                        {
+                            continue;
+                        }
+
+                        // Normalize the revision back to '0' now, as that matches the actual Windows SDK version
+                        windowsSdkVersionParsed = new Version(
+                            windowsSdkVersionParsed.Major,
+                            windowsSdkVersionParsed.Minor,
+                            windowsSdkVersionParsed.Build,
+                            revision: 0);
+
                         if (!knownFrameworkReferencesByWindowsSdkVersion.ContainsKey(windowsSdkVersionParsed))
                         {
                             knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed] = new();
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
index bbcb524d8783..6157e635dbe6 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
@@ -39,6 +39,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Generate KnownFrameworkReference items for the Windows SDK pack -->
     <CreateWindowsSdkKnownFrameworkReferences
       UseWindowsSDKPreview="$(UseWindowsSDKPreview)"
+      UseCsWinRT3="$(_TargetPlatformVersionUsesCsWinRT3)"
       WindowsSdkPackageVersion="$(WindowsSdkPackageVersion)"
       TargetFrameworkIdentifier="$(TargetFrameworkIdentifier)"
       TargetFrameworkVersion="$(_TargetFrameworkVersionWithoutV)"

From a6e227a3f3073910812df6783bc07e056d8bf071 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 15 Jul 2025 11:41:05 -0700
Subject: [PATCH 07/32] Update '_WarnForCsWinRT3_0PreviewFeatureEnabled'

---
 src/Tasks/Common/Resources/Strings.resx                     | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.cs.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.de.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.es.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.fr.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.it.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ja.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ko.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.pl.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf            | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.ru.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.tr.xlf               | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf          | 4 ++--
 src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf          | 4 ++--
 .../targets/Microsoft.NET.TargetFrameworkInference.targets  | 1 +
 .../targets/Microsoft.NET.Windows.targets                   | 6 +++---
 16 files changed, 31 insertions(+), 30 deletions(-)

diff --git a/src/Tasks/Common/Resources/Strings.resx b/src/Tasks/Common/Resources/Strings.resx
index bbebadd53f08..8aed4b94ce9d 100644
--- a/src/Tasks/Common/Resources/Strings.resx
+++ b/src/Tasks/Common/Resources/Strings.resx
@@ -995,7 +995,7 @@ You may need to build the project on another operating system or architecture, o
     <comment>{StrBegins="NETSDK1228: "}</comment>
   </data>
   <data name="UsingPreviewCsWinRT3_0Feature" xml:space="preserve">
-    <value>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</value>
+    <value>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</value>
     <comment>{StrBegins="NETSDK1229: "}</comment>
   </data>
 </root>
\ No newline at end of file
diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
index 4e5b591459c8..fe3e921ff434 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
index 90c80bb7a38a..0c151084d8c2 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.de.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
index 20107e912a1a..aa3c5856ccc4 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.es.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
index ee09bd071ee5..1b7e006c246a 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
index d161406ddd1d..27ca9b58959f 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.it.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
index 3c93be7a54ce..91a272f49a58 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
index 8a5420710946..e68af450895a 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
index 3032f4c2e863..521ea58e1832 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
index 80d63e09ccdf..fc8f98ca8e3e 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
index 5c99f99a2821..9cdb65f4ad0c 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
index 797e7819f3d4..c0524675930b 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
index bc3a782cdc6b..2f7f53147b8b 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
index 1c79bd08a394..2da21edb2171 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
@@ -1044,8 +1044,8 @@ The following are names of parameters or literal values and should not be transl
         <note>{StrBegins="NETSDK1107: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewCsWinRT3_0Feature">
-        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</source>
-        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the build number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the build number to '0' to use CsWinRT 2.x instead.</target>
+        <source>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</source>
+        <target state="new">NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</target>
         <note>{StrBegins="NETSDK1229: "}</note>
       </trans-unit>
       <trans-unit id="UsingPreviewSdk">
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index c4c940e378bf..8b2683f86ce3 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -74,6 +74,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
     <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
     <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
+    <_OriginalWindowsTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'">$(TargetPlatformVersion)</_OriginalWindowsTargetPlatformVersion>
     <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 3)).0</TargetPlatformVersion>
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index 2c126237bfa6..2ab077b6f382 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -169,14 +169,14 @@ Copyright (c) .NET Foundation. All rights reserved.
   </Target>
 
   <!--
-    Emit a warning if using CsWinRT 3.0, which is selected when targeting a Windows SDK with '1' as the patch version.
+    Emit a warning if using CsWinRT 3.0, which is selected when targeting a Windows SDK with '1' as the revision version.
     NOTE: remove this target when CsWinRT 3.0 is released as a stable version and becomes officially supported.
   -->
   <Target Name="_WarnForCsWinRT3_0PreviewFeatureEnabled"
           AfterTargets="ResolvePackageAssets"
             Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true'
-                        and $([System.Version]::Parse('$(TargetPlatformVersion)').Build) == 1">
+                        and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true' ">
     <NETSdkWarning ResourceName="UsingPreviewCsWinRT3_0Feature"
-                   FormatArguments="$(TargetPlatformVersion)" />
+                   FormatArguments="$(_OriginalWindowsTargetPlatformVersion)" />
   </Target>
 </Project>

From 4d465e6add7be72cfe9bb12c7d771a5e5f22fb49 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 16 Jul 2025 14:22:04 -0700
Subject: [PATCH 08/32] Define 'CSWINRT3_0' for CsWinRT 3.0

---
 .../targets/Microsoft.NET.Sdk.BeforeCommon.targets       | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
index 0b94c1b0cbb5..738de91b410b 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
@@ -211,6 +211,15 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_ImplicitDefineConstant Include="$(_PlatformIdentifierForImplicitDefine)" />
       <_ImplicitDefineConstant Include="$(_PlatformIdentifierForImplicitDefine)$(_PlatformVersionForImplicitDefine)" />
     </ItemGroup>
+
+    <!--
+      We support multi-targeting CsWinRT 3.0, which has several breaking changes that consuming projects might require
+      using 'ifdef'-s for, to handle the differences between CsWinRT 2.x and 3.0. So when that is used, we also define
+      a constant. Common scenarios are 'TypedEventHandler<,>' not existing anymore, and interop code being different.
+    -->
+    <ItemGroup Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true' ">
+      <_ImplicitDefineConstant Include="CSWINRT3_0" />
+    </ItemGroup>
   </Target>
 
   <!-- Add OR_GREATER compilation symbols for target frameworks with .NET Framework, .NET Standard, .NET Core, and .NET -->

From 676ece8566df0bb8f7e3c6a82ad5fd3f5879fdb8 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Wed, 16 Jul 2025 14:24:32 -0700
Subject: [PATCH 09/32] Add unit tests

---
 ...ThatWeWantToBuildAWindowsDesktopProject.cs | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index d8c129cf4e5a..3077f48aa4e9 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -498,6 +498,58 @@ public void ItWarnsWhenBuildingAProjectTargetingCsWinRT3_0()
                 .NotHaveStdOutContaining("NETSDK1229");
         }
 
+        [WindowsOnlyFact]
+        public void ItImplicitlyDefinesCSWINRT3_0WhenBuildingAProjectTargetingCsWinRT3_0()
+        {
+            TestProject testProject = new()
+            {
+                Name = "A",
+                ProjectSdk = "Microsoft.NET.Sdk",
+                TargetFrameworks = "net10.0-windows10.0.22621.1",
+                SourceFiles =
+                {
+                    ["Program.cs"] = """
+                    #if !CSWINRT3_0
+                    #error CSWINRT3_0 is not defined
+                    #endif
+                    """
+                }
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass();
+        }
+
+        [WindowsOnlyFact]
+        public void ItDoesNotImplicitlyDefineCSWINRT3_0WhenBuildingAProjectNotTargetingCsWinRT3_0()
+        {
+            TestProject testProject = new()
+            {
+                Name = "A",
+                ProjectSdk = "Microsoft.NET.Sdk",
+                TargetFrameworks = "net10.0-windows10.0.22621.0",
+                SourceFiles =
+                {
+                    ["Program.cs"] = """
+                    #if CSWINRT3_0
+                    #error CSWINRT3_0 is defined
+                    #endif
+                    """
+                }
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass();
+        }
+
         [WindowsOnlyFact]
         public void ItErrorsWhenTargetingBelowNet6WithUseUwpProperty()
         {

From 0c68835b28944cba3b62d2330bf8d253e5028d5a Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Mon, 21 Jul 2025 17:39:42 -0700
Subject: [PATCH 10/32] Revert incorrect 'Strings.resx' change

---
 src/Tasks/Common/Resources/Strings.resx | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Tasks/Common/Resources/Strings.resx b/src/Tasks/Common/Resources/Strings.resx
index 8aed4b94ce9d..29f30cddfaf0 100644
--- a/src/Tasks/Common/Resources/Strings.resx
+++ b/src/Tasks/Common/Resources/Strings.resx
@@ -875,6 +875,7 @@ You may need to build the project on another operating system or architecture, o
   <data name="SolutionProjectConfigurationsConflict" xml:space="preserve">
     <value>NETSDK1197: Multiple solution project(s) contain conflicting '{0}' values; ensure the values match. Consider using a Directory.build.props file to set the property for all projects. Conflicting projects:
 {1}</value>
+  <comment>{StrBegins="NETSDK1197: "}</comment>
   </data>
   <data name="PublishProfileNotPresent" xml:space="preserve">
     <value>NETSDK1198: A publish profile with the name '{0}' was not found in the project. Set the PublishProfile property to a valid file name.</value>

From 58c260c9c4bab4b337c127d915aa8040e785b750 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 22 Jul 2025 09:28:26 -0700
Subject: [PATCH 11/32] Update .xlf files

---
 src/Tasks/Common/Resources/xlf/Strings.cs.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.de.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.es.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.fr.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.it.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.ja.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.ko.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.pl.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf   | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.ru.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.tr.xlf      | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf | 2 +-
 src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf | 2 +-
 13 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
index fe3e921ff434..87fb9f9eaab1 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Projekt(y) několika řešení obsahuj(e/í) konfliktní hodnoty „{0}“; ujistěte se, že se hodnoty shodují. Zvažte použití souboru Directory.build.props k nastavení vlastnosti pro všechny projekty. Konfliktní projekty:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
index 0c151084d8c2..13db3b66ad80 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.de.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Mehrere Projektmappenprojekte enthalten widersprüchliche Werte für "{0}". Stellen Sie sicher, dass die Werte übereinstimmen. Erwägen Sie die Verwendung einer Directory.build.props-Datei, um die Eigenschaft für alle Projekte festzulegen. In Konflikt stehende Projekte: 
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
index aa3c5856ccc4..2ef55a2566fc 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.es.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Varios proyectos de solución que contienen valores '{0}' en conflicto; asegúrese de que los valores coinciden. Considere la posibilidad de usar un archivo Directory.build.props para establecer la propiedad para todos los proyectos. Proyectos en conflicto:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
index 1b7e006c246a..0b448657cef0 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: plusieurs projets de solution contiennent des valeurs '{0}' en conflit ; assurez-vous que les valeurs correspondent. Envisagez d'utiliser un fichier Directory.build.props pour définir la propriété pour tous les projets. Projets conflictuels : 
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
index 27ca9b58959f..79488754fa36 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.it.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: più progetti della soluzione contengono valori '{0}' in conflitto. Verificare che i valori corrispondano. Provare a usare un file Directory.build.props per impostare la proprietà di tutti i progetti. Progetti in conflitto:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
index 91a272f49a58..343228fa2bc9 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: 複数のソリューションのプロジェクトに、競合する '{0}' 値が含まれています。値が一致するようにしてください。Directory.build.props ファイルを使用して、すべてのプロジェクトのプロパティを設定することを検討してください。競合するプロジェクト: 
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
index e68af450895a..c4ba90428660 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: 여러 솔루션 프로젝트에 충돌하는 '{0}' 값이 있습니다. 값이 일치하는지 확인하세요. Directory.build.props 파일을 사용하여 모든 프로젝트에 대한 속성을 설정하는 것이 좋습니다. 충돌하는 프로젝트:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
index 521ea58e1832..2c6e696d798c 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Wiele projektów rozwiązań zawiera wartości „{0}” powodujące konflikt; upewnij się, że wartości są zgodne. Rozważ użycie pliku Directory.build.props na potrzeby ustawienia właściwości dla wszystkich projektów. Projekty powodujące konflikt:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
index fc8f98ca8e3e..7d04fc0bb7a2 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Vários projetos de solução contêm valores '{0}' conflitantes; garantir que os valores correspondam. Considere usar um arquivo Directory.build.props para configurar a propriedade para todos os projetos. Projetos conflitantes:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
index 9cdb65f4ad0c..f84dd5880230 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: несколько проектов решения содержат конфликтующие значения "{0}". Убедитесь, что значения совпадают. Рассмотрите возможность использования файла Directory.build.props для настройки свойства для всех проектов. Конфликтующие проекты:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
index c0524675930b..4ee9ecf510f5 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: Birden çok çözüm projesi çakışan '{0}' değerleri içeriyor; değerlerin eşleştiğinden emin olun. Özelliği tüm projeler için ayarlamak için Directory.build.props dosyası kullanabilirsiniz. Çakışan projeler:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
index 2f7f53147b8b..7bb3fc2b1645 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: 多个解决方案项目包含存在冲突的“{0}”值；请确保值能够匹配。请考虑使用 Directory.build.props 文件设置所有项目的属性。存在冲突的项目:
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
index 2da21edb2171..9aa913f6a506 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
@@ -906,7 +906,7 @@ The following are names of parameters or literal values and should not be transl
 {1}</source>
         <target state="needs-review-translation">NETSDK1197: 多個解決方案專案包含衝突的 '{0}' 值; 請確保值相符。考慮使用 Directory.build.props 檔案來設定所有專案的屬性。衝突的專案: 
 {1}</target>
-        <note />
+        <note>{StrBegins="NETSDK1197: "}</note>
       </trans-unit>
       <trans-unit id="TargetFrameworkIsEol">
         <source>NETSDK1138: The target framework '{0}' is out of support and will not receive security updates in the future. Please refer to {1} for more information about the support policy.</source>

From d8d8cb04b81301f8b676a6e41eb3625cb0393f00 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Tue, 22 Jul 2025 13:53:53 -0700
Subject: [PATCH 12/32] Fix parsing normalized SDK version

---
 .../targets/Microsoft.NET.TargetFrameworkInference.targets     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 8b2683f86ce3..7520708dc52d 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -75,7 +75,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
     <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
     <_OriginalWindowsTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'">$(TargetPlatformVersion)</_OriginalWindowsTargetPlatformVersion>
-    <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 3)).0</TargetPlatformVersion>
+    <_NormalizedWindowsTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</_NormalizedWindowsTargetPlatformVersion>
+    <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'" >$(_NormalizedWindowsTargetPlatformVersion)</TargetPlatformVersion>
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>

From fd4f2749275f84559f01ac057cbd9bf98b905f5d Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Fri, 8 Aug 2025 13:21:46 -0700
Subject: [PATCH 13/32] Fix framework references creation for '.1' TFM

---
 .../CreateWindowsSdkKnownFrameworkReferences.cs       | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index 0035cba55652..aa678faff5e3 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -98,7 +98,16 @@ protected override void ExecuteCore()
                             knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed] = new();
                         }
 
-                        knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed].Add((normalizedMinimumVersion, CreateKnownFrameworkReferences(windowsSdkPackageVersion, TargetFrameworkVersion, supportedWindowsVersion.ItemSpec)));
+                        // We are intentionally using 'Version.ToString(4)' here instead of passing the 'ItemSpec'
+                        // on the current item (even though the version is parsed from it), so that if we are using
+                        // CsWinRT 3.0 and we have reverted the revision number to '0', we will correctly also match
+                        // that in the target platform version string (otherwise that would've been '.1').
+                        var createdKnownFrameworkReferences = CreateKnownFrameworkReferences(
+                            windowsSdkPackageVersion,
+                            TargetFrameworkVersion,
+                            targetPlatformVersion: windowsSdkVersionParsed.ToString(4));
+
+                        knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed].Add((normalizedMinimumVersion, createdKnownFrameworkReferences));
                     }
                 }
 

From 983f97356dacd42afd0eab48cd52b2142059d732 Mon Sep 17 00:00:00 2001
From: Sergio Pedri <sergio0694@live.com>
Date: Thu, 14 Aug 2025 03:02:17 -0700
Subject: [PATCH 14/32] Add unit tests for normalized defines

---
 ...ThatWeWantToBuildAWindowsDesktopProject.cs | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 3077f48aa4e9..2baf232e0b8f 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -550,6 +550,58 @@ public void ItDoesNotImplicitlyDefineCSWINRT3_0WhenBuildingAProjectNotTargetingC
                 .Pass();
         }
 
+        [WindowsOnlyFact]
+        public void ItNormalizesWindowsSDKImplicitDefinesWhenBuildingAProjectTargetingCsWinRT3_0()
+        {
+            TestProject testProject = new()
+            {
+                Name = "A",
+                ProjectSdk = "Microsoft.NET.Sdk",
+                TargetFrameworks = "net10.0-windows10.0.22621.1",
+                SourceFiles =
+                {
+                    ["Program.cs"] = """
+                    #if !WINDOWS10_0_22621_0 || !WINDOWS10_0_22621_0_OR_GREATER || WINDOWS10_0_22621_1 || WINDOWS10_0_22621_1_OR_GREATER
+                    #error Incorrect Windows SDK implicit defines
+                    #endif
+                    """
+                }
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass();
+        }
+
+        [WindowsOnlyFact]
+        public void ItHasExpectedWindowsSDKImplicitDefinesWhenBuildingAProjectTargetingCsWinRT2_0()
+        {
+            TestProject testProject = new()
+            {
+                Name = "A",
+                ProjectSdk = "Microsoft.NET.Sdk",
+                TargetFrameworks = "net10.0-windows10.0.22621.0",
+                SourceFiles =
+                {
+                    ["Program.cs"] = """
+                    #if !WINDOWS10_0_22621_0 || !WINDOWS10_0_22621_0_OR_GREATER || WINDOWS10_0_22621_1 || WINDOWS10_0_22621_1_OR_GREATER
+                    #error Incorrect Windows SDK implicit defines
+                    #endif
+                    """
+                }
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass();
+        }
+
         [WindowsOnlyFact]
         public void ItErrorsWhenTargetingBelowNet6WithUseUwpProperty()
         {

From b38c0924bb36343415fc8d4bb798f61be1584ef8 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Thu, 14 Aug 2025 13:20:05 -0400
Subject: [PATCH 15/32] Switch to using profiles in the same framework
 reference to differentiate between CSWinRT 2 and 3

---
 eng/ManualVersions.props                      | 11 -------
 .../targets/GenerateBundledVersions.targets   | 17 ++--------
 ...reateWindowsSdkKnownFrameworkReferences.cs | 33 +++----------------
 ...T.Sdk.FrameworkReferenceResolution.targets |  1 -
 .../targets/Microsoft.NET.Windows.props       |  5 ++-
 .../targets/Microsoft.NET.Windows.targets     |  8 +++--
 6 files changed, 17 insertions(+), 58 deletions(-)

diff --git a/eng/ManualVersions.props b/eng/ManualVersions.props
index 9738c1935cc5..9b67e035d26a 100644
--- a/eng/ManualVersions.props
+++ b/eng/ManualVersions.props
@@ -9,17 +9,6 @@
   Basically: In this file, choose the highest version when resolving merge conflicts.
  -->
   <PropertyGroup>
-
-    <!-- CsWinRT 3.0 targeting packs -->
-    <MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion>10.0.17763.57</MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion>10.0.18362.57</MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion>10.0.19041.57</MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion>10.0.20348.57</MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion>10.0.22000.57</MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion>10.0.22621.57</MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion>
-    <MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion>10.0.26100.57</MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion>
-
-    <!-- CsWinRT 2.x targeting packs-->
     <MicrosoftWindowsSDKNETRef10_0_17763PackageVersion>10.0.17763.57</MicrosoftWindowsSDKNETRef10_0_17763PackageVersion>
     <MicrosoftWindowsSDKNETRef10_0_18362PackageVersion>10.0.18362.57</MicrosoftWindowsSDKNETRef10_0_18362PackageVersion>
     <MicrosoftWindowsSDKNETRef10_0_19041PackageVersion>10.0.19041.57</MicrosoftWindowsSDKNETRef10_0_19041PackageVersion>
diff --git a/src/Layout/redist/targets/GenerateBundledVersions.targets b/src/Layout/redist/targets/GenerateBundledVersions.targets
index 7f5318cd01b3..9237525dec17 100644
--- a/src/Layout/redist/targets/GenerateBundledVersions.targets
+++ b/src/Layout/redist/targets/GenerateBundledVersions.targets
@@ -1316,21 +1316,8 @@ Copyright (c) .NET Foundation. All rights reserved.
                               TargetingPackName="NETStandard.Library.Ref"
                               TargetingPackVersion="$(NETStandardLibraryRefPackageVersion)"
                               />
-    
-    <!--
-      Supported Windows versions using CsWinRT 3.0 (.NET 10 is the baseline). This leverages the patch version of
-      the Windows SDK version to allow multi-targeting, which is required to allow customers to gradually migrate.
-      Both CsWinRT 3.0 and 2.x will be supported for a period of time, and packages can target both of them.
-    -->
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.20348.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_20348_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.19041.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_19041_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.18362.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_18362_1PackageVersion)" MinimumNETVersion="10.0" />
-    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.17763.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_17763_1PackageVersion)" MinimumNETVersion="10.0" />
-
-    <!-- Supported Windows versions using CsWinRT 2.x -->
+
+    <!-- Supported Windows versions -->
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000PackageVersion)" MinimumNETVersion="8.0" />
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index aa678faff5e3..110c5c1d926e 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -17,8 +17,6 @@ public class CreateWindowsSdkKnownFrameworkReferences : TaskBase
     {
         public bool UseWindowsSDKPreview { get; set; }
 
-        public bool UseCsWinRT3 { get; set; }
-
         public string WindowsSdkPackageVersion { get; set; }
 
         public string TargetFrameworkIdentifier { get; set; }
@@ -78,36 +76,12 @@ protected override void ExecuteCore()
                             continue;
                         }
 
-                        // If we're using CsWinRT 3.0, filter to only items with '1' as the revision number.
-                        // Otherwise, if we're using CsWinRT 2.0, exclude all of them and pick '0' revisions.
-                        if ((UseCsWinRT3 && windowsSdkVersionParsed.Revision == 0) ||
-                            (!UseCsWinRT3 && windowsSdkVersionParsed.Revision == 1))
-                        {
-                            continue;
-                        }
-
-                        // Normalize the revision back to '0' now, as that matches the actual Windows SDK version
-                        windowsSdkVersionParsed = new Version(
-                            windowsSdkVersionParsed.Major,
-                            windowsSdkVersionParsed.Minor,
-                            windowsSdkVersionParsed.Build,
-                            revision: 0);
-
                         if (!knownFrameworkReferencesByWindowsSdkVersion.ContainsKey(windowsSdkVersionParsed))
                         {
                             knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed] = new();
                         }
 
-                        // We are intentionally using 'Version.ToString(4)' here instead of passing the 'ItemSpec'
-                        // on the current item (even though the version is parsed from it), so that if we are using
-                        // CsWinRT 3.0 and we have reverted the revision number to '0', we will correctly also match
-                        // that in the target platform version string (otherwise that would've been '.1').
-                        var createdKnownFrameworkReferences = CreateKnownFrameworkReferences(
-                            windowsSdkPackageVersion,
-                            TargetFrameworkVersion,
-                            targetPlatformVersion: windowsSdkVersionParsed.ToString(4));
-
-                        knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed].Add((normalizedMinimumVersion, createdKnownFrameworkReferences));
+                        knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed].Add((normalizedMinimumVersion, CreateKnownFrameworkReferences(windowsSdkPackageVersion, TargetFrameworkVersion, supportedWindowsVersion.ItemSpec)));
                     }
                 }
 
@@ -125,10 +99,11 @@ protected override void ExecuteCore()
 
         private static TaskItem[] CreateKnownFrameworkReferences(string windowsSdkPackageVersion, string targetFrameworkVersion, string targetPlatformVersion)
         {
-            // Return three items:
+            // Return multiple items for different profiles:
             //   - No profile: with the entire Windows SDK (including Windows.UI.Xaml.* types), only used by downlevel .NET SDKs
             //   - "Windows": just the Windows SDK, without anything in Windows.UI.Xaml.* .dll
             //   - "Xaml": just the Windows.UI.Xaml types
+            //   - "Windows2" and "Xaml2": these profiles use the CSWinRT projections
             //
             // Note: we still need to return the item with no profile even if unused, so that the filtering logic for profiles will work correctly.
             return
@@ -136,6 +111,8 @@ private static TaskItem[] CreateKnownFrameworkReferences(string windowsSdkPackag
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: null),
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Windows"),
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Xaml"),
+                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Windows2"),
+                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Xaml2"),
             ];
         }
 
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
index 6157e635dbe6..bbcb524d8783 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
@@ -39,7 +39,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!-- Generate KnownFrameworkReference items for the Windows SDK pack -->
     <CreateWindowsSdkKnownFrameworkReferences
       UseWindowsSDKPreview="$(UseWindowsSDKPreview)"
-      UseCsWinRT3="$(_TargetPlatformVersionUsesCsWinRT3)"
       WindowsSdkPackageVersion="$(WindowsSdkPackageVersion)"
       TargetFrameworkIdentifier="$(TargetFrameworkIdentifier)"
       TargetFrameworkVersion="$(_TargetFrameworkVersionWithoutV)"
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
index ddd1c2e84097..26251159461f 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
@@ -12,7 +12,10 @@ Copyright (c) .NET Foundation. All rights reserved.
 
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' ">
-    <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.Windows" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All" />
+    <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.Windows" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All"
+                        Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'"/>
+    <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.Windows2" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All"
+                        Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'"/>
   </ItemGroup>
 
   <PropertyGroup>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index e53c2d78ced6..e7d22562d30e 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -66,8 +66,12 @@ Copyright (c) .NET Foundation. All rights reserved.
   <!-- Also add the Windows.UI.Xaml.* projections from the Windows SDK if 'UseUwp' is set in the project.
        Note: we only add this reference if the TFM is .NET 8 or above, as the Windows SDK projections
        that are used on .NET 6 and below do not have the Windows.UI.Xaml profile, so this wouldn't work. -->
-  <ItemGroup Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' ">
-    <FrameworkReference Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '8.0')) and '$(TargetPlatformIdentifier)' == 'Windows' and '$(UseUwp)' == 'true' " Include="Microsoft.Windows.SDK.NET.Ref.Xaml" />
+  <ItemGroup Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' And
+                          '$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '8.0')) and '$(TargetPlatformIdentifier)' == 'Windows' and '$(UseUwp)' == 'true' ">
+    <FrameworkReference Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'"
+                        Include="Microsoft.Windows.SDK.NET.Ref.Xaml" />
+    <FrameworkReference Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'"
+                        Include="Microsoft.Windows.SDK.NET.Ref.Xaml2" />
   </ItemGroup>
 
   <!-- If WindowsSdkPackageVersion is specified and it is an older version before profile support was added, 

From b622290374f289367a46d66c0e5099beafa09114 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Thu, 14 Aug 2025 13:39:53 -0400
Subject: [PATCH 16/32] Add support for WindowsSdkPackageMinimumRevision

---
 .../CreateWindowsSdkKnownFrameworkReferences.cs     | 13 +++++++++++++
 ...oft.NET.Sdk.FrameworkReferenceResolution.targets |  1 +
 2 files changed, 14 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index 110c5c1d926e..677418865f0f 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -19,6 +19,8 @@ public class CreateWindowsSdkKnownFrameworkReferences : TaskBase
 
         public string WindowsSdkPackageVersion { get; set; }
 
+        public string WindowsSdkPackageMinimumRevision { get; set; }
+
         public string TargetFrameworkIdentifier { get; set; }
 
         public string TargetFrameworkVersion { get; set; }
@@ -81,6 +83,17 @@ protected override void ExecuteCore()
                             knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed] = new();
                         }
 
+                        if (!string.IsNullOrEmpty(WindowsSdkPackageMinimumRevision) &&
+                            Version.TryParse(windowsSdkPackageVersion, out var windowsSdkPackageVersionParsed) &&
+                            int.TryParse(WindowsSdkPackageMinimumRevision, out var minimumWindowsSdkRevision))
+                        {
+                            if (windowsSdkPackageVersionParsed.Revision < minimumWindowsSdkRevision)
+                            {
+                                windowsSdkPackageVersionParsed = new Version(windowsSdkPackageVersionParsed.Major, windowsSdkPackageVersionParsed.Minor, windowsSdkPackageVersionParsed.Build, minimumWindowsSdkRevision);
+                                windowsSdkPackageVersion = windowsSdkPackageVersionParsed.ToString();
+                            }
+                        }
+
                         knownFrameworkReferencesByWindowsSdkVersion[windowsSdkVersionParsed].Add((normalizedMinimumVersion, CreateKnownFrameworkReferences(windowsSdkPackageVersion, TargetFrameworkVersion, supportedWindowsVersion.ItemSpec)));
                     }
                 }
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
index bbcb524d8783..f3afef69fd8a 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
@@ -40,6 +40,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <CreateWindowsSdkKnownFrameworkReferences
       UseWindowsSDKPreview="$(UseWindowsSDKPreview)"
       WindowsSdkPackageVersion="$(WindowsSdkPackageVersion)"
+      WindowsSdkPackageMinimumRevision="$(WindowsSdkPackageMinimumRevision)"
       TargetFrameworkIdentifier="$(TargetFrameworkIdentifier)"
       TargetFrameworkVersion="$(_TargetFrameworkVersionWithoutV)"
       TargetPlatformIdentifier="$(TargetPlatformIdentifier)"

From c29c79e391f170540713474e4bd904d8f25a493b Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Thu, 14 Aug 2025 18:43:40 -0700
Subject: [PATCH 17/32] Fix included profiles

---
 .../ResolveRuntimePackAssets.cs                        | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs b/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
index 6e175381569b..9915ccf0d216 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
@@ -92,6 +92,16 @@ protected override void ExecuteCore()
                     {
                         profiles.Add("Xaml");
                     }
+
+                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.Windows2") == true)
+                    {
+                        profiles.Add("Windows2");
+                    }
+                    
+                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.Xaml2") == true)
+                    {
+                        profiles.Add("Xaml2");
+                    }
                 }
 
                 //  If we have a runtime framework with an empty profile, it means that we should use all of the contents of the runtime pack,

From 415c772307f11723057bb4940832f6e48b831b0f Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Mon, 18 Aug 2025 10:14:10 -0400
Subject: [PATCH 18/32] Add CSWinRT 2 and 3 multi-targeting test

---
 ...nThatWeWantToBuildAWindowsDesktopProject.cs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 2baf232e0b8f..08bbb8ccc278 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -749,6 +749,24 @@ public void ItHandlesProfilesWithSelfContained()
             buildCommand.GetOutputDirectory().Should().HaveFile("PresentationFramework.dll");
         }
 
+        [WindowsOnlyFact]
+        public void ItCanMultiTargetCSWinRT2And3()
+        {
+            TestProject testProject = new()
+            {
+                TargetFrameworks = $"{ToolsetInfo.CurrentTargetFramework}-windows10.0.22000.0;{ToolsetInfo.CurrentTargetFramework}-windows10.0.22000.1",
+                IsExe = true,
+                SelfContained = "true",
+                RuntimeIdentifier = "win-x64"
+            };
+
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute().Should().Pass();
+
+        }
+
         private string GetReferencedWindowsSdkVersion(TestAsset testAsset)
         {
             var getValueCommand = new GetValuesCommand(testAsset, "PackageDownload", GetValuesCommand.ValueType.Item)

From d7126cc55565fd725a45e39f985caea5e8199291 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Mon, 18 Aug 2025 18:18:30 -0400
Subject: [PATCH 19/32] Don't normalize to .0 TargetPlatformVersion revision
 for CSWinRT 3

---
 .../targets/GenerateBundledVersions.targets       | 15 ++++++++++++++-
 .../CreateWindowsSdkKnownFrameworkReferences.cs   |  6 +++---
 ...Microsoft.NET.TargetFrameworkInference.targets |  3 ---
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/Layout/redist/targets/GenerateBundledVersions.targets b/src/Layout/redist/targets/GenerateBundledVersions.targets
index 9237525dec17..8db9f625c7a9 100644
--- a/src/Layout/redist/targets/GenerateBundledVersions.targets
+++ b/src/Layout/redist/targets/GenerateBundledVersions.targets
@@ -1317,7 +1317,20 @@ Copyright (c) .NET Foundation. All rights reserved.
                               TargetingPackVersion="$(NETStandardLibraryRefPackageVersion)"
                               />
 
-    <!-- Supported Windows versions -->
+    <!--
+      Supported Windows versions using CsWinRT 3.0 (.NET 10 is the baseline). This leverages the revision of
+      the Windows SDK version to allow multi-targeting, which is required to allow customers to gradually migrate.
+      Both CsWinRT 3.0 and 2.x will be supported for a period of time, and packages can target both of them.
+    -->
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.20348.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_20348PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.19041.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_19041PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.18362.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_18362PackageVersion)" MinimumNETVersion="10.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.17763.1" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_17763PackageVersion)" MinimumNETVersion="10.0" />
+
+    <!-- Supported Windows versions using CsWinRT 2.x -->
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_26100PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22621PackageVersion)" MinimumNETVersion="8.0" />
     <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.0" WindowsSdkPackageVersion="$(MicrosoftWindowsSDKNETRef10_0_22000PackageVersion)" MinimumNETVersion="8.0" />
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index 677418865f0f..a397b6b18b55 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -116,7 +116,7 @@ private static TaskItem[] CreateKnownFrameworkReferences(string windowsSdkPackag
             //   - No profile: with the entire Windows SDK (including Windows.UI.Xaml.* types), only used by downlevel .NET SDKs
             //   - "Windows": just the Windows SDK, without anything in Windows.UI.Xaml.* .dll
             //   - "Xaml": just the Windows.UI.Xaml types
-            //   - "Windows2" and "Xaml2": these profiles use the CSWinRT projections
+            //   - "CsWinRT3.Windows" and "CsWinRT3.Xaml": these profiles use the CSWinRT projections
             //
             // Note: we still need to return the item with no profile even if unused, so that the filtering logic for profiles will work correctly.
             return
@@ -124,8 +124,8 @@ private static TaskItem[] CreateKnownFrameworkReferences(string windowsSdkPackag
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: null),
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Windows"),
                 CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Xaml"),
-                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Windows2"),
-                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "Xaml2"),
+                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "CsWinRT3.Windows"),
+                CreateKnownFrameworkReference(windowsSdkPackageVersion, targetFrameworkVersion, targetPlatformVersion, profile: "CsWinRT3.Xaml"),
             ];
         }
 
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 7520708dc52d..56bfc07eba4f 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -74,9 +74,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     -->
     <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
     <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
-    <_OriginalWindowsTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'">$(TargetPlatformVersion)</_OriginalWindowsTargetPlatformVersion>
-    <_NormalizedWindowsTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</_NormalizedWindowsTargetPlatformVersion>
-    <TargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'" >$(_NormalizedWindowsTargetPlatformVersion)</TargetPlatformVersion>
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>

From 93d669f5514683924d700b39da1d3c66c5bb4d9a Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Mon, 18 Aug 2025 19:09:41 -0700
Subject: [PATCH 20/32] Fix profile names

---
 .../Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs | 8 ++++----
 .../targets/Microsoft.NET.Windows.props                   | 2 +-
 .../targets/Microsoft.NET.Windows.targets                 | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs b/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
index 9915ccf0d216..317f0f217c08 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/ResolveRuntimePackAssets.cs
@@ -93,14 +93,14 @@ protected override void ExecuteCore()
                         profiles.Add("Xaml");
                     }
 
-                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.Windows2") == true)
+                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.CsWinRT3.Windows") == true)
                     {
-                        profiles.Add("Windows2");
+                        profiles.Add("CsWinRT3.Windows");
                     }
                     
-                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.Xaml2") == true)
+                    if (FrameworkReferences?.Any(fxReference => fxReference.ItemSpec == "Microsoft.Windows.SDK.NET.Ref.CsWinRT3.Xaml") == true)
                     {
-                        profiles.Add("Xaml2");
+                        profiles.Add("CsWinRT3.Xaml");
                     }
                 }
 
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
index 26251159461f..d3e75b1f4c78 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.props
@@ -14,7 +14,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   <ItemGroup Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' ">
     <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.Windows" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All"
                         Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'"/>
-    <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.Windows2" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All"
+    <FrameworkReference Include="Microsoft.Windows.SDK.NET.Ref.CsWinRT3.Windows" IsImplicitlyDefined="true" Pack="false" PrivateAssets="All"
                         Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'"/>
   </ItemGroup>
 
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index e7d22562d30e..46713a2890cc 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -71,7 +71,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <FrameworkReference Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'"
                         Include="Microsoft.Windows.SDK.NET.Ref.Xaml" />
     <FrameworkReference Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'"
-                        Include="Microsoft.Windows.SDK.NET.Ref.Xaml2" />
+                        Include="Microsoft.Windows.SDK.NET.Ref.CsWinRT3.Xaml" />
   </ItemGroup>
 
   <!-- If WindowsSdkPackageVersion is specified and it is an older version before profile support was added, 

From ca298da525f5db86e23238fa248fec95db5c624b Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Tue, 19 Aug 2025 00:34:27 -0700
Subject: [PATCH 21/32] Normalize implicit define

---
 .../targets/Microsoft.NET.Sdk.BeforeCommon.targets   | 12 +++++++++++-
 ...soft.NET.WindowsSdkSupportedTargetPlatforms.props |  9 +++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
index 738de91b410b..2fe0cccebe45 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
@@ -206,6 +206,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     <PropertyGroup>
       <_PlatformIdentifierForImplicitDefine>$(TargetPlatformIdentifier.ToUpperInvariant())</_PlatformIdentifierForImplicitDefine>
       <_PlatformVersionForImplicitDefine>$(TargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
+      <!-- Normalize the last part of target platform version to .0 when ending with .1 as that indicates the use of the CsWinRT 3.0 verison. -->
+      <_PlatformVersionForImplicitDefine Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true' ">$([System.Text.RegularExpressions.Regex]::Replace($(_PlatformVersionForImplicitDefine), '_1$', '_0'))</_PlatformVersionForImplicitDefine>
     </PropertyGroup>
     <ItemGroup>
       <_ImplicitDefineConstant Include="$(_PlatformIdentifierForImplicitDefine)" />
@@ -243,7 +245,15 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target Name="GeneratePlatformCompatibleDefineConstants"
           Condition=" '$(DisableImplicitFrameworkDefines)' != 'true' and '$(TargetPlatformIdentifier)' != '' and '$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), 5.0)) " >
     <ItemGroup>
-      <_SupportedPlatformCompatibleVersions Include="@(SdkSupportedTargetPlatformVersion)" Condition=" %(Identity) != '' and $([MSBuild]::VersionLessThanOrEquals(%(Identity), $(TargetPlatformVersion))) " />
+      <!--
+        Prefer the normalized version of the supported target platform version when available.
+        This allows to drop the .1 at the end of the version in CsWinRT 3.0 scenarios and 
+        use a common define for both CsWinRT 3.0 and CsWinRT 2.x.
+      -->
+      <_SupportedPlatformCompatibleVersions Include="@(SdkSupportedTargetPlatformVersion)"
+                                            Condition=" %(Identity) != '' and '%(SdkSupportedTargetPlatformVersion.NormalizedSupportedTargetPlatformVersion)' == '' and $([MSBuild]::VersionLessThanOrEquals(%(Identity), $(TargetPlatformVersion))) " />
+      <_SupportedPlatformCompatibleVersions Include="@(SdkSupportedTargetPlatformVersion->'%(NormalizedSupportedTargetPlatformVersion)')"
+                                            Condition=" '%(SdkSupportedTargetPlatformVersion.NormalizedSupportedTargetPlatformVersion)' != '' and $([MSBuild]::VersionLessThanOrEquals('%(SdkSupportedTargetPlatformVersion.NormalizedSupportedTargetPlatformVersion)', $(TargetPlatformVersion))) " />
       <_ImplicitDefineConstant Include="@(_SupportedPlatformCompatibleVersions->Distinct()->'$(TargetPlatformIdentifier.ToUpper())%(Identity)_OR_GREATER'->Replace('.', '_'))" />
     </ItemGroup>
   </Target>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
index 34439118b427..81b1047d31d3 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
@@ -22,7 +22,12 @@ Copyright (c) .NET Foundation. All rights reserved.
         <WindowsSdkSupportedTargetPlatformVersion Include="7.0" />
     </ItemGroup>
 
-    <ItemGroup>
-        <SdkSupportedTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows'" Include="@(WindowsSdkSupportedTargetPlatformVersion)" />
+    <ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'Windows'">
+        <!-- Normalize the last part of TFM to .0 when ending with .1 as that indicates the use of the CsWinRT 3.0 verison. -->
+        <_NormalizedWindowsSdkSupportedTargetPlatformVersion Include="@(WindowsSdkSupportedTargetPlatformVersion)">
+            <NormalizedSupportedTargetPlatformVersion 
+                Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(Identity)', '^\d+\.\d+\.\d+\.1$'))">$([System.Version]::Parse('%(Identity)').Major).$([System.Version]::Parse('%(Identity)').Minor).$([System.Version]::Parse('%(Identity)').Build).0</NormalizedSupportedTargetPlatformVersion>
+        </_NormalizedWindowsSdkSupportedTargetPlatformVersion>
+        <SdkSupportedTargetPlatformVersion Include="@(_NormalizedWindowsSdkSupportedTargetPlatformVersion)" />
     </ItemGroup>
 </Project>

From 95fdd4b9dc3a01b08ef4e3a8d5b72655de5b39fb Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Tue, 19 Aug 2025 08:49:35 -0700
Subject: [PATCH 22/32] Fix SupportedOSPlatformVersion and tests

---
 .../targets/Microsoft.NET.Sdk.BeforeCommon.targets    |  5 ++---
 .../targets/Microsoft.NET.Sdk.targets                 |  3 ++-
 .../Microsoft.NET.TargetFrameworkInference.targets    |  3 ++-
 .../targets/Microsoft.NET.Windows.targets             |  4 ++++
 .../GivenThatWeWantToBuildAWindowsDesktopProject.cs   | 11 ++++++++++-
 5 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
index 2fe0cccebe45..567e061e5bb9 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
@@ -205,9 +205,8 @@ Copyright (c) .NET Foundation. All rights reserved.
         Condition=" '$(DisableImplicitFrameworkDefines)' != 'true' and '$(TargetPlatformIdentifier)' != '' and '$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), 5.0)) " >
     <PropertyGroup>
       <_PlatformIdentifierForImplicitDefine>$(TargetPlatformIdentifier.ToUpperInvariant())</_PlatformIdentifierForImplicitDefine>
-      <_PlatformVersionForImplicitDefine>$(TargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
-      <!-- Normalize the last part of target platform version to .0 when ending with .1 as that indicates the use of the CsWinRT 3.0 verison. -->
-      <_PlatformVersionForImplicitDefine Condition=" '$(IncludeWindowsSDKRefFrameworkReferences)' == 'true' and '$(_TargetPlatformVersionUsesCsWinRT3)' == 'true' ">$([System.Text.RegularExpressions.Regex]::Replace($(_PlatformVersionForImplicitDefine), '_1$', '_0'))</_PlatformVersionForImplicitDefine>
+      <_PlatformVersionForImplicitDefine Condition="'$(EffectiveTargetPlatformVersion)' != ''">$(EffectiveTargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
+      <_PlatformVersionForImplicitDefine Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
     </PropertyGroup>
     <ItemGroup>
       <_ImplicitDefineConstant Include="$(_PlatformIdentifierForImplicitDefine)" />
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
index 08a659ee9fb6..42de115a6a98 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
@@ -1499,7 +1499,8 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <!-- Default SupportedOSPlatformVersion to TargetPlatformVersion -->
   <PropertyGroup Condition="'$(SupportedOSPlatformVersion)' == ''">
-    <SupportedOSPlatformVersion>$(TargetPlatformVersion)</SupportedOSPlatformVersion>
+    <SupportedOSPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' != ''">$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
+    <SupportedOSPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion)</SupportedOSPlatformVersion>
   </PropertyGroup>
 
   <Import Project="$(AfterMicrosoftNETSdkTargets)" Condition="'$(AfterMicrosoftNETSdkTargets)' != ''"/>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 56bfc07eba4f..af7bc4c46119 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -73,7 +73,8 @@ Copyright (c) .NET Foundation. All rights reserved.
       immediately reset the revision number back to '.0' so that the rest of the tooling continues to see the same version as before.
     -->
     <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
-    <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
+    <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(TargetPlatformVersion)' != '' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
+    <EffectiveTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(TargetPlatformVersion)' != ''">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</EffectiveTargetPlatformVersion>
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index 46713a2890cc..50ca01ffad57 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -40,6 +40,10 @@ Copyright (c) .NET Foundation. All rights reserved.
     <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(TargetPlatformMinVersion)</SupportedOSPlatformVersion>
     <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(SupportedOSPlatformVersion)</TargetPlatformMinVersion>
 
+    <!-- If neither were set, then use the EffectiveTargetPlatformVersion value for both if set. -->
+    <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
+    <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(EffectiveTargetPlatformVersion)</TargetPlatformMinVersion>
+
     <!-- If neither were set, then use the TargetPlatformVersion value for both -->
     <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(TargetPlatformVersion)</SupportedOSPlatformVersion>
     <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(TargetPlatformVersion)</TargetPlatformMinVersion>
diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 08bbb8ccc278..39a8fb83130e 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -487,6 +487,8 @@ public void ItWarnsWhenBuildingAProjectTargetingCsWinRT3_0()
                 ProjectSdk = "Microsoft.NET.Sdk",
                 TargetFrameworks = "net10.0-windows10.0.22621.1"
             };
+            // Disabling until CsWinRTGen is available.
+            testProject.AdditionalProperties["CsWinRTGenerateInteropAssembly"] = "false";
 
             var testAsset = _testAssetsManager.CreateTestProject(testProject);
 
@@ -495,7 +497,7 @@ public void ItWarnsWhenBuildingAProjectTargetingCsWinRT3_0()
                 .Should()
                 .Pass()
                 .And
-                .NotHaveStdOutContaining("NETSDK1229");
+                .HaveStdOutContaining("NETSDK1229");
         }
 
         [WindowsOnlyFact]
@@ -515,6 +517,8 @@ public void ItImplicitlyDefinesCSWINRT3_0WhenBuildingAProjectTargetingCsWinRT3_0
                     """
                 }
             };
+            // Disabling until CsWinRTGen is available.
+            testProject.AdditionalProperties["CsWinRTGenerateInteropAssembly"] = "false";
 
             var testAsset = _testAssetsManager.CreateTestProject(testProject);
 
@@ -567,6 +571,9 @@ public void ItNormalizesWindowsSDKImplicitDefinesWhenBuildingAProjectTargetingCs
                     """
                 }
             };
+            // Disabling until CsWinRTGen is available.
+            testProject.AdditionalProperties["CsWinRTGenerateInteropAssembly"] = "false";
+
 
             var testAsset = _testAssetsManager.CreateTestProject(testProject);
 
@@ -759,6 +766,8 @@ public void ItCanMultiTargetCSWinRT2And3()
                 SelfContained = "true",
                 RuntimeIdentifier = "win-x64"
             };
+            // Disabling until CsWinRTGen is available.
+            testProject.AdditionalProperties["CsWinRTGenerateInteropAssembly"] = "false";
 
             var testAsset = _testAssetsManager.CreateTestProject(testProject);
 

From 0787215fb099cf3406effa1149af00311b2b64ee Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Tue, 19 Aug 2025 16:39:37 -0700
Subject: [PATCH 23/32] Fix tests and always set EffectiveTargetPlatformVersion

---
 .../targets/Microsoft.NET.Sdk.BeforeCommon.targets       | 3 +--
 .../targets/Microsoft.NET.Sdk.targets                    | 4 ++--
 .../Microsoft.NET.TargetFrameworkInference.targets       | 9 ++++++---
 .../targets/Microsoft.NET.Windows.targets                | 7 ++-----
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
index 567e061e5bb9..03551d1f1440 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.BeforeCommon.targets
@@ -205,8 +205,7 @@ Copyright (c) .NET Foundation. All rights reserved.
         Condition=" '$(DisableImplicitFrameworkDefines)' != 'true' and '$(TargetPlatformIdentifier)' != '' and '$(TargetFrameworkIdentifier)' == '.NETCoreApp' and $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), 5.0)) " >
     <PropertyGroup>
       <_PlatformIdentifierForImplicitDefine>$(TargetPlatformIdentifier.ToUpperInvariant())</_PlatformIdentifierForImplicitDefine>
-      <_PlatformVersionForImplicitDefine Condition="'$(EffectiveTargetPlatformVersion)' != ''">$(EffectiveTargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
-      <_PlatformVersionForImplicitDefine Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
+      <_PlatformVersionForImplicitDefine>$(EffectiveTargetPlatformVersion.Replace('.', '_'))</_PlatformVersionForImplicitDefine>
     </PropertyGroup>
     <ItemGroup>
       <_ImplicitDefineConstant Include="$(_PlatformIdentifierForImplicitDefine)" />
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
index 42de115a6a98..a620593ceda8 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
@@ -1493,14 +1493,14 @@ Copyright (c) .NET Foundation. All rights reserved.
          weren't included in the TargetPlatformMoniker for restore, obscuring the errors about unknown platforms or missing
          workloads. -->
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == ''">0.0</TargetPlatformVersion>
+    <EffectiveTargetPlatformVersion>$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <TargetPlatformMoniker>$(TargetPlatformIdentifier),Version=$(TargetPlatformVersion)</TargetPlatformMoniker>
     <TargetPlatformDisplayName>$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKDisplayName($(TargetPlatformIdentifier), $(TargetPlatformVersion)))</TargetPlatformDisplayName>
   </PropertyGroup>
 
   <!-- Default SupportedOSPlatformVersion to TargetPlatformVersion -->
   <PropertyGroup Condition="'$(SupportedOSPlatformVersion)' == ''">
-    <SupportedOSPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' != ''">$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
-    <SupportedOSPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion)</SupportedOSPlatformVersion>
+    <SupportedOSPlatformVersion>$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
   </PropertyGroup>
 
   <Import Project="$(AfterMicrosoftNETSdkTargets)" Condition="'$(AfterMicrosoftNETSdkTargets)' != ''"/>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index af7bc4c46119..e28c7793b932 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -57,6 +57,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   
   <PropertyGroup>
     <_TargetFrameworkVersionWithoutV>$(TargetFrameworkVersion.TrimStart('vV'))</_TargetFrameworkVersionWithoutV>
+    <EffectiveTargetPlatformVersion>$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
   </PropertyGroup>
 
   <!--
@@ -69,15 +70,17 @@ Copyright (c) .NET Foundation. All rights reserved.
     <!--
       In order to support multi-targeting between CsWinRT 2.x and CsWinRT 3.0, we use the revision number of the Windows SDK to indicate the CsWinRT version.
       Specifically, '.0' indicates CsWinRT 2.x, and '.1' indicates CsWinRT 3.0. Because we want the rest of the tooling to still always see the '.0' version
-      for the Windows SDK (as the '.1' only has meaning for the .NET SDK), here we check if we're using CsWinRT 3.0, and if so we store that result and then
-      immediately reset the revision number back to '.0' so that the rest of the tooling continues to see the same version as before.
+      for the Windows SDK (as the '.1' only has meaning for the .NET SDK and TFM in NuGet), here we check if we're using CsWinRT 3.0, and if so we have a version
+      of the target platform version with the revision number reset back to '.0' as EffectiveTargetPlatformVersion which we use in other places.
+      EffectiveTargetPlatformVersion is set to TargetPlatformVersion in other scenarios.
     -->
     <_TargetPlatformVersionUsesCsWinRT3>false</_TargetPlatformVersionUsesCsWinRT3>
     <_TargetPlatformVersionUsesCsWinRT3 Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(TargetPlatformVersion)' != '' and $([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
-    <EffectiveTargetPlatformVersion Condition="'$(TargetPlatformIdentifier)' == 'Windows' and '$(TargetPlatformVersion)' != ''">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</EffectiveTargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</EffectiveTargetPlatformVersion>
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'false'">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <!-- Normalize casing of windows to Windows -->
     <TargetPlatformIdentifier Condition="'$(TargetPlatformIdentifier)' == 'Windows'">Windows</TargetPlatformIdentifier>
   </PropertyGroup>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index 50ca01ffad57..de769380ef45 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -32,6 +32,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   <!-- Set 7.0 as the TargetPlatformVersion for windows. -->
   <PropertyGroup Condition="'$(TargetPlatformIdentifier)' == 'windows' and '$(TargetPlatformVersion)' == ''" >
     <TargetPlatformVersion>7.0</TargetPlatformVersion>
+    <EffectiveTargetPlatformVersion>$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetPlatformIdentifier)' == 'Windows'">
@@ -40,13 +41,9 @@ Copyright (c) .NET Foundation. All rights reserved.
     <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(TargetPlatformMinVersion)</SupportedOSPlatformVersion>
     <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(SupportedOSPlatformVersion)</TargetPlatformMinVersion>
 
-    <!-- If neither were set, then use the EffectiveTargetPlatformVersion value for both if set. -->
+    <!-- If neither were set, then use the EffectiveTargetPlatformVersion value for both. -->
     <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
     <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(EffectiveTargetPlatformVersion)</TargetPlatformMinVersion>
-
-    <!-- If neither were set, then use the TargetPlatformVersion value for both -->
-    <SupportedOSPlatformVersion Condition="'$(SupportedOSPlatformVersion)' == ''">$(TargetPlatformVersion)</SupportedOSPlatformVersion>
-    <TargetPlatformMinVersion Condition="'$(TargetPlatformMinVersion)' == ''">$(TargetPlatformVersion)</TargetPlatformMinVersion>
   </PropertyGroup>
 
   <!-- Used by analyzers in the Microsoft.Windows.SDK.NET.Ref package. -->

From 2dffc351c6f7fec3770648bc2ab612070774208a Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Tue, 19 Aug 2025 20:22:22 -0700
Subject: [PATCH 24/32] Fix TargetPlatformVersion being set in
 Directory.Build.targets

---
 .../targets/Microsoft.NET.Sdk.targets             |  6 +++++-
 ...Microsoft.NET.TargetFrameworkInference.targets |  3 +--
 .../targets/Microsoft.NET.Windows.targets         | 15 +++++++++++++++
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
index a620593ceda8..e557003b02d4 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets
@@ -1493,11 +1493,15 @@ Copyright (c) .NET Foundation. All rights reserved.
          weren't included in the TargetPlatformMoniker for restore, obscuring the errors about unknown platforms or missing
          workloads. -->
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == ''">0.0</TargetPlatformVersion>
-    <EffectiveTargetPlatformVersion>$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <TargetPlatformMoniker>$(TargetPlatformIdentifier),Version=$(TargetPlatformVersion)</TargetPlatformMoniker>
     <TargetPlatformDisplayName>$([Microsoft.Build.Utilities.ToolLocationHelper]::GetPlatformSDKDisplayName($(TargetPlatformIdentifier), $(TargetPlatformVersion)))</TargetPlatformDisplayName>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <!-- If the Windows targets wasn't called to default it, then just default it to the TargetPlatformVersion. -->
+    <EffectiveTargetPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
+  </PropertyGroup>
+
   <!-- Default SupportedOSPlatformVersion to TargetPlatformVersion -->
   <PropertyGroup Condition="'$(SupportedOSPlatformVersion)' == ''">
     <SupportedOSPlatformVersion>$(EffectiveTargetPlatformVersion)</SupportedOSPlatformVersion>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index e28c7793b932..1dadaf19c08b 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -57,7 +57,6 @@ Copyright (c) .NET Foundation. All rights reserved.
   
   <PropertyGroup>
     <_TargetFrameworkVersionWithoutV>$(TargetFrameworkVersion.TrimStart('vV'))</_TargetFrameworkVersionWithoutV>
-    <EffectiveTargetPlatformVersion>$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
   </PropertyGroup>
 
   <!--
@@ -80,7 +79,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
-    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'false'">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <!-- Normalize casing of windows to Windows -->
     <TargetPlatformIdentifier Condition="'$(TargetPlatformIdentifier)' == 'Windows'">Windows</TargetPlatformIdentifier>
   </PropertyGroup>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
index de769380ef45..19f9cdcf9a65 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets
@@ -29,6 +29,21 @@ Copyright (c) .NET Foundation. All rights reserved.
     <TargetPlatformVersionSupported>true</TargetPlatformVersionSupported>
   </PropertyGroup>
 
+  <!-- If EffectiveTargetPlatformVersion isn't set, then someone may have manually set TargetPlatformVersion in their Directory.Build.targets
+       which wasn't processed before. -->
+  <PropertyGroup Condition="'$(TargetPlatformIdentifier)' == 'windows' and '$(TargetPlatformVersion)' != '' and '$(EffectiveTargetPlatformVersion)' == ''" >
+    <!--
+      In order to support multi-targeting between CsWinRT 2.x and CsWinRT 3.0, we use the revision number of the Windows SDK to indicate the CsWinRT version.
+      Specifically, '.0' indicates CsWinRT 2.x, and '.1' indicates CsWinRT 3.0. Because we want the rest of the tooling to still always see the '.0' version
+      for the Windows SDK (as the '.1' only has meaning for the .NET SDK and TFM in NuGet), here we check if we're using CsWinRT 3.0, and if so we have a version
+      of the target platform version with the revision number reset back to '.0' as EffectiveTargetPlatformVersion which we use in other places.
+      EffectiveTargetPlatformVersion is set to TargetPlatformVersion in other scenarios.
+    -->
+    <_TargetPlatformVersionUsesCsWinRT3 Condition="$([System.Version]::Parse('$(TargetPlatformVersion)').Revision) == 1">true</_TargetPlatformVersionUsesCsWinRT3>
+    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' == 'true'">$([System.Version]::Parse('$(TargetPlatformVersion)').Major).$([System.Version]::Parse('$(TargetPlatformVersion)').Minor).$([System.Version]::Parse('$(TargetPlatformVersion)').Build).0</EffectiveTargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
+  </PropertyGroup>
+
   <!-- Set 7.0 as the TargetPlatformVersion for windows. -->
   <PropertyGroup Condition="'$(TargetPlatformIdentifier)' == 'windows' and '$(TargetPlatformVersion)' == ''" >
     <TargetPlatformVersion>7.0</TargetPlatformVersion>

From ffbdf9eb59f666c3055f8b1905a70e00d18ab80f Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <manodasan@hotmail.com>
Date: Wed, 20 Aug 2025 15:23:59 -0700
Subject: [PATCH 25/32] Apply suggestion from @dsplaisted

Co-authored-by: Daniel Plaisted <dsplaisted@gmail.com>
---
 .../targets/Microsoft.NET.TargetFrameworkInference.targets      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 1dadaf19c08b..57ac3804a631 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -79,7 +79,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
-    <EffectiveTargetPlatformVersion Condition="'$(_TargetPlatformVersionUsesCsWinRT3)' != 'true'">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(EffectiveTargetPlatformVersion )' == ''">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <!-- Normalize casing of windows to Windows -->
     <TargetPlatformIdentifier Condition="'$(TargetPlatformIdentifier)' == 'Windows'">Windows</TargetPlatformIdentifier>
   </PropertyGroup>

From 8d29560ef788b231d697863dfc9ed9c61e6aaee4 Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Wed, 20 Aug 2025 17:30:10 -0700
Subject: [PATCH 26/32] Fix typo

---
 .../targets/Microsoft.NET.TargetFrameworkInference.targets      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
index 57ac3804a631..08e5f714b4f6 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.TargetFrameworkInference.targets
@@ -79,7 +79,7 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     <TargetPlatformVersion Condition="'$(TargetPlatformVersion)' == '' or ('$(TargetPlatformIdentifier)' == 'Windows' and !$([MSBuild]::VersionGreaterThanOrEquals($(TargetPlatformVersion), 10.0)))" >$([MSBuild]::GetTargetPlatformVersion('$(TargetFramework)', 2))</TargetPlatformVersion>
     <TargetPlatformVersion Condition="$([MSBuild]::VersionEquals($(TargetPlatformVersion), 0.0))" ></TargetPlatformVersion>
-    <EffectiveTargetPlatformVersion Condition="'$(EffectiveTargetPlatformVersion )' == ''">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
+    <EffectiveTargetPlatformVersion Condition="'$(EffectiveTargetPlatformVersion)' == ''">$(TargetPlatformVersion)</EffectiveTargetPlatformVersion>
     <!-- Normalize casing of windows to Windows -->
     <TargetPlatformIdentifier Condition="'$(TargetPlatformIdentifier)' == 'Windows'">Windows</TargetPlatformIdentifier>
   </PropertyGroup>

From 62fa6b696e71921ea3d6d8216180547aaf4990de Mon Sep 17 00:00:00 2001
From: Manodasan Wignarajah <mawign@microsoft.com>
Date: Wed, 20 Aug 2025 18:31:13 -0700
Subject: [PATCH 27/32] Use version parse instead

---
 .../Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
index 81b1047d31d3..0a33b09d81f8 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.WindowsSdkSupportedTargetPlatforms.props
@@ -26,7 +26,7 @@ Copyright (c) .NET Foundation. All rights reserved.
         <!-- Normalize the last part of TFM to .0 when ending with .1 as that indicates the use of the CsWinRT 3.0 verison. -->
         <_NormalizedWindowsSdkSupportedTargetPlatformVersion Include="@(WindowsSdkSupportedTargetPlatformVersion)">
             <NormalizedSupportedTargetPlatformVersion 
-                Condition="$([System.Text.RegularExpressions.Regex]::IsMatch('%(Identity)', '^\d+\.\d+\.\d+\.1$'))">$([System.Version]::Parse('%(Identity)').Major).$([System.Version]::Parse('%(Identity)').Minor).$([System.Version]::Parse('%(Identity)').Build).0</NormalizedSupportedTargetPlatformVersion>
+                Condition="$([System.Version]::Parse('%(Identity)').Revision) == 1">$([System.Version]::Parse('%(Identity)').Major).$([System.Version]::Parse('%(Identity)').Minor).$([System.Version]::Parse('%(Identity)').Build).0</NormalizedSupportedTargetPlatformVersion>
         </_NormalizedWindowsSdkSupportedTargetPlatformVersion>
         <SdkSupportedTargetPlatformVersion Include="@(_NormalizedWindowsSdkSupportedTargetPlatformVersion)" />
     </ItemGroup>

From 09e3f53d52129a18fa6a986f082ca2b4daa00f58 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Wed, 27 Aug 2025 13:43:51 -0400
Subject: [PATCH 28/32] Add tests and additional error case for
 WindowsSdkPackageMinimumRevision

---
 src/Tasks/Common/Resources/Strings.resx       |  8 ++-
 src/Tasks/Common/Resources/xlf/Strings.cs.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.de.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.es.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.fr.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.it.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.ja.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.ko.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.pl.xlf |  5 ++
 .../Common/Resources/xlf/Strings.pt-BR.xlf    |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.ru.xlf |  5 ++
 src/Tasks/Common/Resources/xlf/Strings.tr.xlf |  5 ++
 .../Common/Resources/xlf/Strings.zh-Hans.xlf  |  5 ++
 .../Common/Resources/xlf/Strings.zh-Hant.xlf  |  5 ++
 ...reateWindowsSdkKnownFrameworkReferences.cs | 14 +++++
 ...ThatWeWantToBuildAWindowsDesktopProject.cs | 54 +++++++++++++++++++
 16 files changed, 139 insertions(+), 2 deletions(-)

diff --git a/src/Tasks/Common/Resources/Strings.resx b/src/Tasks/Common/Resources/Strings.resx
index 29f30cddfaf0..8bd022cc5c4b 100644
--- a/src/Tasks/Common/Resources/Strings.resx
+++ b/src/Tasks/Common/Resources/Strings.resx
@@ -982,7 +982,6 @@ You may need to build the project on another operating system or architecture, o
     <value>NETSDK1225: Native compilation is not supported when invoking the Publish target directly. Try running dotnet publish.</value>
     <comment>{StrBegins="NETSDK1225: "}</comment>
   </data>
-  <!-- The latest message added is PrunePackageDataNotFound. Please update this value with each PR to catch parallel PRs both adding a new message -->
   <data name="PrunePackageDataNotFound" xml:space="preserve">
     <value>NETSDK1226: Prune Package data not found {0} {1} {2}.  To ignore this error, set the AllowMissingPrunePackageData to true.</value>
     <comment>{StrBegins="NETSDK1226: "}</comment>
@@ -999,4 +998,9 @@ You may need to build the project on another operating system or architecture, o
     <value>NETSDK1229: Targeting a Windows SDK version with '1' as the revision number will reference CsWinRT 3.0, which is currently in preview. The current project is targeting the Windows SDK version '{0}'. If this is not intended, change the revision number to '0' to use CsWinRT 2.x instead.</value>
     <comment>{StrBegins="NETSDK1229: "}</comment>
   </data>
-</root>
\ No newline at end of file
+  <data name="CantSpecifyBothProperties" xml:space="preserve">
+    <value>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</value>
+    <comment>{StrBegins="NETSDK1230: "}</comment>
+  </data>
+  <!-- The latest message added is CantSpecifyBothProperties. Please update this value with each PR to catch parallel PRs both adding a new message -->
+</root>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
index 87fb9f9eaab1..33eefab224e0 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.cs.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: Publikování do jednoho souboru se podporuje jen pro cíl netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Volí se {0}, protože verze sestavení {1} je větší než {2}.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.de.xlf b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
index 13db3b66ad80..de8cd2d4dcd6 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.de.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.de.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: Das Veröffentlichen in einer einzelnen Datei wird nur für das netcoreapp-Ziel unterstützt.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Auswahl von "{0}", weil AssemblyVersion {1} höher ist als {2}.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.es.xlf b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
index 2ef55a2566fc..992d17ed0e87 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.es.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.es.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: La publicación en un único archivo solo se admite para el destino netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Se elegirá "{0}" porque AssemblyVersion "{1}" es mayor que "{2}".</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
index 0b448657cef0..f1fa539c671d 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.fr.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: la publication sur un seul fichier est uniquement prise en charge pour une cible netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">'{0}' choisi, car AssemblyVersion '{1}' est supérieur à '{2}'.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.it.xlf b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
index 79488754fa36..80df52af6e60 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.it.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.it.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: la pubblicazione in un file singolo è supportata solo per la destinazione netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Verrà scelto '{0}' perché il valore di AssemblyVersion '{1}' è maggiore di '{2}'.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
index 343228fa2bc9..0855513cab25 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ja.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: 1 つのファイルへの発行は netcoreapp ターゲットでのみサポートされています。</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">AssemblyVersion '{1}' が '{2}' より大きいため、'{0}' を選択しています。</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
index c4ba90428660..3af9fd77229c 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ko.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: 단일 파일에 게시는 netcoreapp 대상에만 지원됩니다.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">AssemblyVersion '{1}'이(가) '{2}'보다 크기 때문에 '{0}'을(를) 선택합니다.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
index 2c6e696d798c..9075e67ffbdb 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pl.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: Publikowanie do pojedynczego pliku jest obsługiwane tylko w przypadku elementu docelowego netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Zostanie wybrany element „{0}”, ponieważ wartość atrybutu AssemblyVersion „{1}” jest większa niż „{2}”.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
index 7d04fc0bb7a2..6018e8c57fe3 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.pt-BR.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: há suporte para a publicação em um único arquivo somente para o destino netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Escolhendo '{0}' porque AssemblyVersion '{1}' é maior que '{2}'.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
index f84dd5880230..200069017dc3 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.ru.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: публикация в один файл поддерживается только для целевой платформы netcoreapp.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">Используется "{0}", так как значение AssemblyVersion "{1}" больше "{2}".</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
index 4ee9ecf510f5..aa99e0293764 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.tr.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: Tek dosyada yayımlama yalnızca netcoreapp hedefi için desteklenir.</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">'{1}' AssemblyVersion değeri '{2}' değerinden büyük olduğundan '{0}' seçiliyor.</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
index 7bb3fc2b1645..5823f6b3bdbe 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hans.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: 仅 netcoreapp 目标支持发布到单个文件。</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">选择“{0}”，因为 AssemblyVersion“{1}”高于“{2}”。</target>
diff --git a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
index 9aa913f6a506..cf81a058e906 100644
--- a/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
+++ b/src/Tasks/Common/Resources/xlf/Strings.zh-Hant.xlf
@@ -212,6 +212,11 @@
         <target state="translated">NETSDK1125: 只有 netcoreapp 目標支援發行到單一檔案。</target>
         <note>{StrBegins="NETSDK1125: "}</note>
       </trans-unit>
+      <trans-unit id="CantSpecifyBothProperties">
+        <source>NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</source>
+        <target state="new">NETSDK1230: The {0} and {1} properties cannot both be specified. Remove one or the other.</target>
+        <note>{StrBegins="NETSDK1230: "}</note>
+      </trans-unit>
       <trans-unit id="ChoosingAssemblyVersion_Info">
         <source>Choosing '{0}' because AssemblyVersion '{1}' is greater than '{2}'.</source>
         <target state="translated">因為 AssemblyVersion '{1}' 大於 '{2}'，所以選擇 '{0}'。</target>
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
index a397b6b18b55..814248f08205 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/CreateWindowsSdkKnownFrameworkReferences.cs
@@ -38,6 +38,20 @@ protected override void ExecuteCore()
         {
             List<ITaskItem> knownFrameworkReferences = new();
 
+            if (!string.IsNullOrEmpty(WindowsSdkPackageMinimumRevision))
+            {
+                if (!string.IsNullOrEmpty(WindowsSdkPackageVersion))
+                {
+                    Log.LogError(Strings.CantSpecifyBothProperties, nameof(WindowsSdkPackageVersion), nameof(WindowsSdkPackageMinimumRevision));
+                    return;
+                }
+                if (UseWindowsSDKPreview)
+                {
+                    Log.LogError(Strings.CantSpecifyBothProperties, nameof(UseWindowsSDKPreview), nameof(WindowsSdkPackageMinimumRevision));
+                    return;
+                }
+            }
+
             if (!string.IsNullOrEmpty(WindowsSdkPackageVersion))
             {
                 knownFrameworkReferences.AddRange(CreateKnownFrameworkReferences(WindowsSdkPackageVersion, TargetFrameworkVersion, TargetPlatformVersion));
diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 39a8fb83130e..7072d0731eea 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -773,7 +773,61 @@ public void ItCanMultiTargetCSWinRT2And3()
 
             var buildCommand = new BuildCommand(testAsset);
             buildCommand.Execute().Should().Pass();
+        }
+
+        [WindowsOnlyTheory]
+        [InlineData("57", "10.0.19041.57")]
+        [InlineData("50", "10.0.19041.55")]
+        public void MinimumWindowsSdkPackagRevisionCanBeSet(string minimumRevision, string expectedPackageVersion)
+        {
+            var testProject = new TestProject()
+            {
+                TargetFrameworks = $"{ToolsetInfo.CurrentTargetFramework}-windows10.0.19041.0"
+            };
+            testProject.AdditionalProperties["WindowsSdkPackageMinimumRevision"] = minimumRevision;
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
 
+            File.WriteAllText(Path.Combine(testAsset.TestRoot, "Directory.Build.targets"), """
+<Project>
+  <ItemGroup>
+    <WindowsSdkSupportedTargetPlatformVersion Remove="*" />
+
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.26100.0" WindowsSdkPackageVersion="10.0.26100.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22621.0" WindowsSdkPackageVersion="10.0.22621.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.22000.0" WindowsSdkPackageVersion="10.0.22000.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.20348.0" WindowsSdkPackageVersion="10.0.20348.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.19041.0" WindowsSdkPackageVersion="10.0.19041.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.18362.0" WindowsSdkPackageVersion="10.0.18362.55" MinimumNETVersion="8.0" />
+    <WindowsSdkSupportedTargetPlatformVersion Include="10.0.17763.0" WindowsSdkPackageVersion="10.0.17763.55" MinimumNETVersion="8.0" />
+  </ItemGroup>
+</Project>
+""");
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Pass();
+            string referencedWindowsSdkVersion = GetReferencedWindowsSdkVersion(testAsset);
+            referencedWindowsSdkVersion.Should().Be(expectedPackageVersion);
+        }
+
+        [WindowsOnlyFact]
+        public void WindowsSdkPackageVersionAndMinimumRevisionCannotBothBeSpecified()
+        {
+            var testProject = new TestProject()
+            {
+                TargetFrameworks = $"{ToolsetInfo.CurrentTargetFramework}-windows10.0.19041.0"
+            };
+            testProject.AdditionalProperties["WindowsSdkPackageVersion"] = "10.0.19041.55";
+            testProject.AdditionalProperties["WindowsSdkPackageMinimumRevision"] = "57";
+            var testAsset = _testAssetsManager.CreateTestProject(testProject);
+
+            var buildCommand = new BuildCommand(testAsset);
+            buildCommand.Execute()
+                .Should()
+                .Fail()
+                .And
+                .HaveStdOutContaining("NETSDK1230");
         }
 
         private string GetReferencedWindowsSdkVersion(TestAsset testAsset)

From 45d1d9b934953a0ac669f1012bd17ec342bb3b4c Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Wed, 3 Sep 2025 21:04:42 -0400
Subject: [PATCH 29/32] Collect binlog for test

---
 .../GivenThatWeWantToBuildAWindowsDesktopProject.cs           | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
index 7072d0731eea..382259bff48c 100644
--- a/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
+++ b/test/Microsoft.NET.Build.Tests/GivenThatWeWantToBuildAWindowsDesktopProject.cs
@@ -578,7 +578,9 @@ public void ItNormalizesWindowsSDKImplicitDefinesWhenBuildingAProjectTargetingCs
             var testAsset = _testAssetsManager.CreateTestProject(testProject);
 
             var buildCommand = new BuildCommand(testAsset);
-            buildCommand.Execute()
+            buildCommand
+                .WithWorkingDirectory(testAsset.TestRoot)
+                .Execute("-bl")
                 .Should()
                 .Pass();
         }

From dd54f2a611da85aa303bbed2c82c2938dc93be26 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Fri, 5 Sep 2025 16:33:10 -0400
Subject: [PATCH 30/32] Copilot implementation of new logic for stage 2 bundled
 versions

Copilot prompt #1:

Replace the #class:'Microsoft.DotNet.Build.Tasks.OverrideAndCreateBundledNETCoreAppPackageVersion':1164-10242 Task.

The new version should take as parameters the path to the stage 0  bundled versions file as well as the version from stage 2.  It should copy some version numbers from items in the stage 0 version to the stage 2 version, and then save the updated stage 2 version.

It should update items where the TargetFramework metadata is not the latest target framework supported.  There are multiple item types that need to be updated, and they need to be matched on specific metadata.

KnownFrameworkReference: match on Include, TargetFramework metadata.  Update LatestRuntimeFrameworkVersion and TargetingPackVersion
KnownAppHostPack: match on Include, TargetFramework metadata.  Update AppHostPackVersion
KnownCrossgen2Pack: match on Include, TargetFramework.  Update Crossgen2PackVersion
KnownILCompilerPack: match on Include, TargetFramework.  Update ILCompilerPackVersion
KnownRuntimePack: match on Include, TargetFramework, RuntimePackLabels.  Update LatestRuntimeFrameworkVersion
KnownILLinkPack: match on Include, TargetFramework.  Update ILLinkPackVersion.

If there is more than one match based on the specified metadata, generate an error.

For the metadata which is not used to match and is not updated, if the value differs between the stage 0 and stage 2 versions, log a message.

Copilot prompt #2:

Don't look at just the first ItemGroup in each file, load items from all ItemGroups found.

When looking for the latest target framework, use the NuGetFramework class to parse the TargetFramework values, and to compare them.
---
 ...ndCreateBundledNETCoreAppPackageVersion.cs | 247 ++++++------------
 1 file changed, 76 insertions(+), 171 deletions(-)

diff --git a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
index 06445c959111..a9f489f8f554 100644
--- a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
+++ b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
@@ -9,196 +9,101 @@
 using System.Xml.Linq;
 using Microsoft.Build.Framework;
 using Microsoft.Build.Utilities;
-using NuGet.Versioning;
+using System.Collections.Generic;
+using NuGet.Frameworks;
 
 namespace Microsoft.DotNet.Build.Tasks
 {
     /// <summary>
-    /// Use the runtime in dotnet/sdk instead of in the stage 0 to avoid circular dependency.
-    /// If there is a change depended on the latest runtime. Without override the runtime version in BundledNETCoreAppPackageVersion
-    /// we would need to somehow get this change in without the test, and then insertion dotnet/installer
-    /// and then update the stage 0 back.
-    ///
-    /// Override NETCoreSdkVersion to stage 0 sdk version like 6.0.100-dev
-    /// Override NETCoreSdkRuntimeIdentifier and NETCoreSdkPortableRuntimeIdentifier to match the target RID
-    ///
-    /// Use a task to override since it was generated as a string literal replace anyway.
-    /// And using C# can have better error when anything goes wrong.
+    /// Updates version numbers in the stage 2 bundled versions file by copying values from the stage 0 file
+    /// for items where the TargetFramework is not the latest supported. Matches and updates multiple item types.
     /// </summary>
     public sealed class OverrideAndCreateBundledNETCoreAppPackageVersion : Task
     {
-        private static string _messageWhenMismatch =
-            "{0} version {1} does not match BundledNETCoreAppPackageVersion {2}. " +
-            "The schema of https://github.com/dotnet/installer/blob/main/src/redist/targets/GenerateBundledVersions.targets might change. " +
-            "We need to ensure we can swap the runtime version from what's in stage0 to what dotnet/sdk used successfully";
-
-        [Required] public string Stage0MicrosoftNETCoreAppRefPackageVersionPath { get; set; }
-
-        [Required] public string MicrosoftNETCoreAppRefPackageVersion { get; set; }
-
-        [Required] public string NewSDKVersion { get; set; }
-
-        [Required] public string TargetRid { get; set; }
-
+        [Required] public string Stage0BundledVersionsPath { get; set; }
+        [Required] public string Stage2BundledVersionsPath { get; set; }
         [Required] public string OutputPath { get; set; }
 
         public override bool Execute()
         {
-            File.WriteAllText(OutputPath,
-                ExecuteInternal(
-                    File.ReadAllText(Stage0MicrosoftNETCoreAppRefPackageVersionPath),
-                    MicrosoftNETCoreAppRefPackageVersion,
-                    NewSDKVersion,
-                    TargetRid,
-                    Log));
-            return true;
-        }
-
-        public static string ExecuteInternal(
-            string stage0MicrosoftNETCoreAppRefPackageVersionContent,
-            string microsoftNETCoreAppRefPackageVersion,
-            string newSDKVersion,
-            string targetRid,
-            TaskLoggingHelper log)
-        {
-            var projectXml = XDocument.Parse(stage0MicrosoftNETCoreAppRefPackageVersionContent);
-
-            var ns = projectXml.Root.Name.Namespace;
-
-            var propertyGroup = projectXml.Root.Elements(ns + "PropertyGroup").First();            
-
-            propertyGroup.Element(ns + "NETCoreSdkVersion").Value = newSDKVersion;
-            propertyGroup.Element(ns + "NETCoreSdkRuntimeIdentifier").Value = targetRid;
-            propertyGroup.Element(ns + "NETCoreSdkPortableRuntimeIdentifier").Value = targetRid;
-
-
-            var originalBundledNETCoreAppPackageVersion = propertyGroup.Element(ns + "BundledNETCoreAppPackageVersion").Value;
-            var parsedOriginalBundledPackageVersion = SemanticVersion.Parse(originalBundledNETCoreAppPackageVersion);
-            var parsedMicrosoftNETCoreAppRefPackageVersion =
-                SemanticVersion.Parse(microsoftNETCoreAppRefPackageVersion);
-
-            // In the case where we have a new major version, it'll come in first through the dotnet/runtime flow of the
-            // SDK's own package references. The Stage0 SDK's bundled version props file will still be on the older major version
-            // (and the older TFM that goes along with that). If we just replaced the bundled version with the new major version,
-            // apps that target the 'older' TFM would fail to build. So we need to keep the bundled version from the existing
-            // bundledversions.props in this one specific case.
-
-            var newBundledPackageVersion =
-                parsedOriginalBundledPackageVersion.Major == parsedMicrosoftNETCoreAppRefPackageVersion.Major
-                ? microsoftNETCoreAppRefPackageVersion
-                : originalBundledNETCoreAppPackageVersion;
-
-            propertyGroup.Element(ns + "BundledNETCoreAppPackageVersion").Value = newBundledPackageVersion;
-
-            var isNETServicing = IsNETServicing(originalBundledNETCoreAppPackageVersion);
-            var currentTargetFramework = $"net{parsedMicrosoftNETCoreAppRefPackageVersion.Major}.0";
-
-            void CheckAndReplaceElement(XElement element)
+            try
             {
-                if (element.Value != originalBundledNETCoreAppPackageVersion)
+                var stage0Doc = XDocument.Load(Stage0BundledVersionsPath);
+                var stage2Doc = XDocument.Load(Stage2BundledVersionsPath);
+                var ns = stage2Doc.Root.Name.Namespace;
+
+                // Load all items from all ItemGroups
+                var items2 = stage2Doc.Root.Elements(ns + "ItemGroup").SelectMany(ig => ig.Elements()).ToList();
+                var items0 = stage0Doc.Root.Elements(ns + "ItemGroup").SelectMany(ig => ig.Elements()).ToList();
+
+                // Find latest TargetFramework using NuGetFramework
+                var allTargetFrameworks = items2
+                    .Select(e => e.Attribute("TargetFramework")?.Value)
+                    .Where(v => !string.IsNullOrEmpty(v))
+                    .Distinct()
+                    .Select(tf => new { Raw = tf, Parsed = NuGetFramework.Parse(tf) })
+                    .ToList();
+                var latest = allTargetFrameworks
+                    .OrderByDescending(tf => tf.Parsed, NuGetFramework.Comparer)
+                    .FirstOrDefault();
+                var latestTargetFramework = latest?.Raw;
+
+                // Helper for matching and updating
+                void UpdateItems(string elementName, string[] matchAttrs, string[] updateAttrs)
                 {
-                    throw new InvalidOperationException(string.Format(
-                        _messageWhenMismatch,
-                        element.ToString(), element.Value, originalBundledNETCoreAppPackageVersion));
+                    var items2Filtered = items2
+                        .Where(e => e.Name.LocalName == elementName && e.Attribute("TargetFramework")?.Value != latestTargetFramework)
+                        .ToList();
+                    foreach (var item2 in items2Filtered)
+                    {
+                        var matches0 = items0
+                            .Where(e => e.Name.LocalName == elementName && matchAttrs.All(attr => (e.Attribute(attr)?.Value ?? "") == (item2.Attribute(attr)?.Value ?? "")))
+                            .ToList();
+                        if (matches0.Count == 0)
+                        {
+                            Log.LogError($"No matching {elementName} in stage 0 for: {string.Join(", ", matchAttrs.Select(a => $"{a}={item2.Attribute(a)?.Value}"))}");
+                            continue;
+                        }
+                        if (matches0.Count > 1)
+                        {
+                            Log.LogError($"Multiple matches for {elementName} in stage 0 for: {string.Join(", ", matchAttrs.Select(a => $"{a}={item2.Attribute(a)?.Value}"))}");
+                            continue;
+                        }
+                        var item0 = matches0[0];
+                        foreach (var updateAttr in updateAttrs)
+                        {
+                            var v0 = item0.Attribute(updateAttr)?.Value;
+                            var v2 = item2.Attribute(updateAttr)?.Value;
+                            if (v0 != null && v2 != v0)
+                                item2.SetAttributeValue(updateAttr, v0);
+                        }
+                        // Log if other metadata differs
+                        foreach (var attr in item2.Attributes())
+                        {
+                            if (matchAttrs.Contains(attr.Name.LocalName) || updateAttrs.Contains(attr.Name.LocalName))
+                                continue;
+                            var v0 = item0.Attribute(attr.Name)?.Value;
+                            if (v0 != null && v0 != attr.Value)
+                                Log.LogMessage(MessageImportance.Low, $"{elementName} {string.Join(", ", matchAttrs.Select(a => $"{a}={item2.Attribute(a)?.Value}"))}: Metadata '{attr.Name}' differs: stage0='{v0}', stage2='{attr.Value}'");
+                        }
+                    }
                 }
 
-                log.LogMessage(MessageImportance.High,
-                    $"Replacing element {element.Name} value '{element.Value}' with '{newBundledPackageVersion}'");
-                element.Value = newBundledPackageVersion;
-            }
+                UpdateItems("KnownFrameworkReference", new[] { "Include", "TargetFramework" }, new[] { "LatestRuntimeFrameworkVersion", "TargetingPackVersion" });
+                UpdateItems("KnownAppHostPack", new[] { "Include", "TargetFramework" }, new[] { "AppHostPackVersion" });
+                UpdateItems("KnownCrossgen2Pack", new[] { "Include", "TargetFramework" }, new[] { "Crossgen2PackVersion" });
+                UpdateItems("KnownILCompilerPack", new[] { "Include", "TargetFramework" }, new[] { "ILCompilerPackVersion" });
+                UpdateItems("KnownRuntimePack", new[] { "Include", "TargetFramework", "RuntimePackLabels" }, new[] { "LatestRuntimeFrameworkVersion" });
+                UpdateItems("KnownILLinkPack", new[] { "Include", "TargetFramework" }, new[] { "ILLinkPackVersion" });
 
-            void CheckAndReplaceAttribute(XAttribute attribute)
-            {
-                if (attribute.Value != originalBundledNETCoreAppPackageVersion)
-                {
-                    throw new InvalidOperationException(string.Format(
-                        _messageWhenMismatch,
-                        attribute.Parent.ToString() + " --- " + attribute.ToString(), attribute.Value,
-                        originalBundledNETCoreAppPackageVersion));
-                }
-
-                log.LogMessage(MessageImportance.High,
-                    $"Replacing attribute {attribute.Name} value '{attribute.Value}' with '{newBundledPackageVersion}' in element {attribute.Parent.Name}");
-                attribute.Value = newBundledPackageVersion;
+                stage2Doc.Save(OutputPath);
+                return !Log.HasLoggedErrors;
             }
-
-            if (!isNETServicing)
+            catch (Exception ex)
             {
-                CheckAndReplaceElement(propertyGroup.Element(ns + "BundledNETCorePlatformsPackageVersion"));
+                Log.LogErrorFromException(ex, true);
+                return false;
             }
-
-            var itemGroup = projectXml.Root.Elements(ns + "ItemGroup").First();
-
-            if (!isNETServicing)
-            {
-                foreach (var element in itemGroup.Elements(ns + "KnownFrameworkReference")
-                    .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-                {
-                    CheckAndReplaceAttribute(element.Attribute("DefaultRuntimeFrameworkVersion"));
-                    CheckAndReplaceAttribute(element.Attribute("TargetingPackVersion"));
-                }
-            }
-
-            foreach (var element in itemGroup.Elements(ns + "KnownFrameworkReference")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("LatestRuntimeFrameworkVersion"));
-            }
-            foreach (var element in itemGroup.Elements(ns + "KnownAppHostPack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("AppHostPackVersion"));
-            }
-            
-            foreach (var element in itemGroup.Elements(ns + "KnownCrossgen2Pack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("Crossgen2PackVersion"));
-            }
-            
-            foreach (var element in itemGroup.Elements(ns + "KnownILCompilerPack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("ILCompilerPackVersion"));
-            }
-            
-            foreach (var element in itemGroup.Elements(ns + "KnownILLinkPack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("ILLinkPackVersion"));
-            }
-            
-            // web assembly packs always use the latest regardless of the TFM
-            foreach (var element in itemGroup.Elements(ns + "KnownWebAssemblySdkPack"))
-            {
-                CheckAndReplaceAttribute(element.Attribute("WebAssemblySdkPackVersion"));
-            }
-            
-            foreach (var element in itemGroup.Elements(ns + "KnownAspNetCorePack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("AspNetCorePackVersion"));
-            }
-
-            foreach (var element in itemGroup.Elements(ns + "KnownRuntimePack")
-                .Where(e => e.Attribute("TargetFramework")?.Value == currentTargetFramework))
-            {
-                CheckAndReplaceAttribute(element.Attribute("LatestRuntimeFrameworkVersion"));
-            }
-
-            return projectXml.ToString();
-        }
-
-        /// <summary>
-        /// For SDK servicing, few Attributes like "DefaultRuntimeFrameworkVersion" does not use the latest flowed version
-        /// so there is no need to replace them.
-        /// </summary>
-        /// <returns></returns>
-        private static bool IsNETServicing(string netVersion)
-        {
-            var parsedSdkVersion = NuGet.Versioning.NuGetVersion.Parse(netVersion);
-
-            return !parsedSdkVersion.IsPrerelease;
         }
     }
 }

From f61552633fcc622cd9f64e2adc47ae71edc097c6 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Fri, 5 Sep 2025 16:45:24 -0400
Subject: [PATCH 31/32] Fixup/edits to copilot code

---
 src/Layout/redist/targets/OverlaySdkOnLKG.targets    |  7 ++-----
 ...errideAndCreateBundledNETCoreAppPackageVersion.cs | 12 +++++++-----
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/Layout/redist/targets/OverlaySdkOnLKG.targets b/src/Layout/redist/targets/OverlaySdkOnLKG.targets
index 406f81137c2f..19505de69d50 100644
--- a/src/Layout/redist/targets/OverlaySdkOnLKG.targets
+++ b/src/Layout/redist/targets/OverlaySdkOnLKG.targets
@@ -37,11 +37,8 @@
           UseHardLinksIfPossible="true" />
 
     <OverrideAndCreateBundledNETCoreAppPackageVersion
-      Stage0MicrosoftNETCoreAppRefPackageVersionPath="$(_DotNetHiveRoot)/sdk/$(Stage0SdkVersion)/Microsoft.NETCoreSdk.BundledVersions.props"
-      MicrosoftNETCoreAppRefPackageVersion="$(MicrosoftNETCoreAppRefPackageVersion)"
-      NewSDKVersion="$(Version)"
-      TargetRid="$(TargetRid)"
-      OutputPath="$(TestHostDotNetRoot)/sdk/$(Version)/Microsoft.NETCoreSdk.BundledVersions.props"/>
+      Stage0BundledVersionsPath="$(_DotNetHiveRoot)/sdk/$(Stage0SdkVersion)/Microsoft.NETCoreSdk.BundledVersions.props"
+      Stage2BundledVersionsPath="$(TestHostDotNetRoot)/sdk/$(Version)/Microsoft.NETCoreSdk.BundledVersions.props"/>
   </Target>
 
   <Target Name="PublishTestWorkloads"
diff --git a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
index a9f489f8f554..ba4cc47edcb1 100644
--- a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
+++ b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
@@ -15,14 +15,16 @@
 namespace Microsoft.DotNet.Build.Tasks
 {
     /// <summary>
-    /// Updates version numbers in the stage 2 bundled versions file by copying values from the stage 0 file
-    /// for items where the TargetFramework is not the latest supported. Matches and updates multiple item types.
+    /// For stage 2, we want use the version numbers from stage 0 for the downlevel .NET versions.  This is because
+    /// the latest patches of different major versions are built entirely separately, and we want to have tests
+    /// on downlevel versions but we can't depend on the latest patches being available in test environments.
+    ///
+    /// So we copy the version numbers from stage 0 for those downlevel versions.    
     /// </summary>
     public sealed class OverrideAndCreateBundledNETCoreAppPackageVersion : Task
     {
         [Required] public string Stage0BundledVersionsPath { get; set; }
         [Required] public string Stage2BundledVersionsPath { get; set; }
-        [Required] public string OutputPath { get; set; }
 
         public override bool Execute()
         {
@@ -44,7 +46,7 @@ public override bool Execute()
                     .Select(tf => new { Raw = tf, Parsed = NuGetFramework.Parse(tf) })
                     .ToList();
                 var latest = allTargetFrameworks
-                    .OrderByDescending(tf => tf.Parsed, NuGetFramework.Comparer)
+                    .OrderByDescending(tf => tf.Parsed.Version)
                     .FirstOrDefault();
                 var latestTargetFramework = latest?.Raw;
 
@@ -96,7 +98,7 @@ void UpdateItems(string elementName, string[] matchAttrs, string[] updateAttrs)
                 UpdateItems("KnownRuntimePack", new[] { "Include", "TargetFramework", "RuntimePackLabels" }, new[] { "LatestRuntimeFrameworkVersion" });
                 UpdateItems("KnownILLinkPack", new[] { "Include", "TargetFramework" }, new[] { "ILLinkPackVersion" });
 
-                stage2Doc.Save(OutputPath);
+                stage2Doc.Save(Stage2BundledVersionsPath);
                 return !Log.HasLoggedErrors;
             }
             catch (Exception ex)

From 670d7fc690e4f1029486efae78901a1308326106 Mon Sep 17 00:00:00 2001
From: Daniel Plaisted <daplaist@microsoft.com>
Date: Tue, 16 Sep 2025 13:37:57 -0400
Subject: [PATCH 32/32] Remove unnecessary usings

---
 .../OverrideAndCreateBundledNETCoreAppPackageVersion.cs    | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
index ba4cc47edcb1..842c867d7180 100644
--- a/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
+++ b/src/Tasks/sdk-tasks/OverrideAndCreateBundledNETCoreAppPackageVersion.cs
@@ -3,13 +3,6 @@
 
 #nullable disable
 
-using System;
-using System.IO;
-using System.Linq;
-using System.Xml.Linq;
-using Microsoft.Build.Framework;
-using Microsoft.Build.Utilities;
-using System.Collections.Generic;
 using NuGet.Frameworks;
 
 namespace Microsoft.DotNet.Build.Tasks