diff --git a/.drone.jsonnet b/.drone.jsonnet
index 9442280..96ad270 100644
--- a/.drone.jsonnet
+++ b/.drone.jsonnet
@@ -249,12 +249,24 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
     ),
 
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1 Strict",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest', CXXFLAGS: '/permissive-' },
+    ),
+
     windows_pipeline(
         "Windows VS2019 msvc-14.2",
         "cppalliance/dronevs2019",
         { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest' },
     ),
 
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2 Strict",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest', CXXFLAGS: '/permissive-' },
+    ),
+
     windows_pipeline(
         "Windows VS2022 msvc-14.3",
         "cppalliance/dronevs2022:1",
diff --git a/.drone/drone.bat b/.drone/drone.bat
index 66aaf78..4509c7f 100644
--- a/.drone/drone.bat
+++ b/.drone/drone.bat
@@ -20,4 +20,5 @@ b2 -d0 headers
 
 if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
 if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker
diff --git a/appveyor.yml b/appveyor.yml
index baa4199..ecba9be 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -21,6 +21,11 @@ environment:
       TOOLSET: msvc-14.1
       ADDRMD: 32,64
       CXXSTD: 14,17,latest
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      TOOLSET: msvc-14.1
+      ADDRMD: 32,64
+      CXXSTD: 14,17,latest
+      CXXFLAGS: /permissive-
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       TOOLSET: clang-win
       ADDRMD: 64
@@ -51,4 +56,5 @@ build: off
 test_script:
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
   - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
-  - b2 -j3 libs/variant2/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker
+  - if not "%CXXFLAGS%" == "" set CXXFLAGS=cxxflags=%CXXFLAGS%
+  - b2 -j3 libs/variant2/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% %CXXFLAGS% variant=debug,release embed-manifest-via=linker