diff --git a/.github/instructions/cppwinrt.instructions.md b/.github/instructions/cppwinrt.instructions.md
index ba5d66212..eae2fc3c6 100644
--- a/.github/instructions/cppwinrt.instructions.md
+++ b/.github/instructions/cppwinrt.instructions.md
@@ -25,7 +25,7 @@
 - Use VS Developer Shell for correct toolset environment
 - `cmake --build build --config Release --target cppwinrt` for cppwinrt.exe (or MSBuild: `msbuild cppwinrt\cppwinrt.vcxproj /p:Configuration=Release /p:Platform=x64`)
 - NuGet tests: `msbuild test\nuget\NuGetTest.sln /p:Configuration=Release /p:Platform=x64`
-- Module test projects require v145 toolset (VS 2026). Directory.Build.Props sets v143 by default — override with `<PlatformToolset>v145</PlatformToolset>` in Configuration PropertyGroup
+- Module test projects require v145 toolset (VS 2026). Directory.Build.Props selects v145 when VisualStudioVersion >= 18.0 (VS 2026) and falls back to v143 otherwise; override `<PlatformToolset>` in the Configuration PropertyGroup to force a specific toolset
 
 ## Key Patterns
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6c2a04353..37f42ab70 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,8 +15,6 @@ jobs:
         arch: [x86, x64, arm64]
         config: [Debug, Release]
         toolchain:
-          - image: windows-2025
-            platform_toolset: v143
           - image: windows-2025-vs2026
             platform_toolset: v145
         exclude:
@@ -99,10 +97,8 @@ jobs:
         compiler: [MSVC, clang-cl]
         arch: [x86, x64, arm64]
         config: [Debug, Release]
-        test_exe: [test, test_nocoro, test_cpp20, test_cpp20_no_sourcelocation, test_fast, test_slow, test_old, test_module_lock_custom, test_module_lock_none]
+        test_exe: [test, test_nocoro, test_cpp20, test_cpp20_no_sourcelocation, test_cpp20_module, test_fast, test_slow, test_old, test_module_lock_custom, test_module_lock_none]
         toolchain:
-          - image: windows-2025
-            platform_toolset: v143
           - image: windows-2025-vs2026
             platform_toolset: v145
         exclude:
@@ -112,6 +108,9 @@ jobs:
             arch: arm64
           - compiler: clang-cl
             config: Release
+          # C++20 named modules require the MSVC v145 toolset; clang-cl is not supported.
+          - compiler: clang-cl
+            test_exe: test_cpp20_module
     runs-on: ${{ matrix.toolchain.image }}
     steps:
       - uses: actions/checkout@v6
@@ -295,7 +294,7 @@ jobs:
         arch: [x86, x64, arm64]
         config: [Release]
         Deployment: [Component, Standalone]
-    runs-on: windows-latest
+    runs-on: windows-2025-vs2026
     steps:
       - uses: actions/checkout@v6
 
@@ -316,7 +315,7 @@ jobs:
           $target_configuration = "${{ matrix.config }}"
           $target_platform = "${{ matrix.arch }}"
           $target_version = "999.999.999.999"
-          Add-Content $env:GITHUB_ENV "msbuild_config_props=/p:Configuration=$target_configuration,Platform=$target_platform,CppWinRTBuildVersion=$target_version"
+          Add-Content $env:GITHUB_ENV "msbuild_config_props=/p:Configuration=$target_configuration,Platform=$target_platform,CppWinRTBuildVersion=$target_version,PlatformToolset=v145"
 
       - name: Restore nuget packages
         run: |
@@ -336,8 +335,6 @@ jobs:
         arch: [x86, x64]
         config: [Release]
         toolchain:
-          - image: windows-2025
-            platform_toolset: v143
           - image: windows-2025-vs2026
             platform_toolset: v145
     runs-on: ${{ matrix.toolchain.image }}
@@ -378,15 +375,6 @@ jobs:
           $target_configuration = "${{ matrix.config }}"
           $target_platform = "${{ matrix.arch }}"
           & "_build\$target_platform\$target_configuration\cppwinrt.exe" -in local -out _build\$target_platform\$target_configuration -verbose
-      
-      - name: Remove module test projects on v143
-        if: matrix.toolchain.platform_toolset == 'v143'
-        run: |
-          # Module test projects require v145 toolset
-          mv test\nuget\NugetTest.sln test\nuget\NugetTest.sln.orig
-          Get-Content test\nuget\NugetTest.sln.orig |
-            Where-Object { -not ($_ -match 'TestModule') } |
-            Set-Content test\nuget\NugetTest.sln
 
       - name: Run nuget test
         run: |
@@ -394,7 +382,7 @@ jobs:
 
   build-nuget:
     name: Build nuget package with MSVC
-    runs-on: windows-latest
+    runs-on: windows-2025-vs2026
     steps:
       - uses: actions/checkout@v6
 
diff --git a/Directory.Build.Props b/Directory.Build.Props
index c98cd5dd0..5972803c0 100644
--- a/Directory.Build.Props
+++ b/Directory.Build.Props
@@ -3,7 +3,10 @@
   <!-- Set common MSBuild properties and item metadata for CppWinRT tool and tests -->
 
   <PropertyGroup>
+    <!-- Use the v145 toolset on Visual Studio 2026 (VisualStudioVersion 18.0) and later,
+         where it is available; fall back to v143 on older Visual Studio (e.g. 2022). -->
     <PlatformToolset>v143</PlatformToolset>
+    <PlatformToolset Condition="'$(VisualStudioVersion)' &gt;= '18.0'">v145</PlatformToolset>
     <WindowsTargetPlatformVersion>10.0</WindowsTargetPlatformVersion>
     <WindowsTargetPlatformMinVersion>10.0.18362.0</WindowsTargetPlatformMinVersion>
   </PropertyGroup>
diff --git a/test/nuget/TestProxyStub/TestProxyStub.vcxproj b/test/nuget/TestProxyStub/TestProxyStub.vcxproj
index 69e41cfba..cd646da7f 100644
--- a/test/nuget/TestProxyStub/TestProxyStub.vcxproj
+++ b/test/nuget/TestProxyStub/TestProxyStub.vcxproj
@@ -40,7 +40,6 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Label="Configuration">
     <ConfigurationType>DynamicLibrary</ConfigurationType>
-    <PlatformToolset>v143</PlatformToolset>
     <CharacterSet>Unicode</CharacterSet>
   </PropertyGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />