diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7d53ec2f..c862810a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -148,7 +148,7 @@ jobs:
       - name: Grab install script
         run: wget https://apt.llvm.org/llvm.sh && chmod u+x llvm.sh
       - name: Install clang 18 packages
-        run: sudo ./llvm.sh 19 && clang++-19 --version
+        run: sudo ./llvm.sh 18 && clang++-18 --version
       - name: Checkout main boost
         run: git clone -b develop --depth 1 https://github.com/boostorg/boost.git ../boost-root
       - name: Update tools/boostdep
@@ -166,6 +166,9 @@ jobs:
       - name: Generate headers
         run: ./b2 headers
         working-directory: ../boost-root
+      - name: Test Config
+        run: CXXFLAGS=clang++-18 ./config/clang.sh ./config/test_has_module_support.cpp ./config/has_module_support.cpp has_module_support
+        working-directory: ../boost-root/libs/regex/test/module
       - name: Test
         run: CXXFLAGS=clang++-18 ./test.sh ./config/clang.sh
         working-directory: ../boost-root/libs/regex/test/module
@@ -399,6 +402,9 @@ jobs:
       - name: Test
         run: ..\..\..\b2 --hash %ARGS%
         working-directory: ../boost-root/libs/regex/test
+      - name: Module Test
+        run: msvc_test.bat
+        working-directory: ../boost-root/libs/regex/test/module
   ubuntu-cmake-install:
     runs-on: ubuntu-20.04
     strategy:
diff --git a/test/module/msvc_test.bat b/test/module/msvc_test.bat
new file mode 100644
index 00000000..ee984c4e
--- /dev/null
+++ b/test/module/msvc_test.bat
@@ -0,0 +1,8 @@
+REM Basic command line to build everything with msvc:
+
+cl /std:c++latest /EHsc /nologo /W4 /c "%VCToolsInstallDir%\modules\std.ixx"
+cl /std:c++latest /EHsc /nologo /W4 /c /interface /I ..\..\..\.. ..\..\module\regex.cxx
+
+for %%f in (*.cpp) do (
+   cl /std:c++latest /EHsc /nologo /W4 /I ..\..\..\.. %%f std.obj regex.obj
+)
\ No newline at end of file