diff --git a/.github/workflows/ubuntu22-gcc13.yml b/.github/workflows/ubuntu22-gcc13.yml
index 7757f8a..d6aea23 100644
--- a/.github/workflows/ubuntu22-gcc13.yml
+++ b/.github/workflows/ubuntu22-gcc13.yml
@@ -14,10 +14,10 @@ jobs:
           CXX=g++-13 CXXFLAGS=-Werror cmake -DFASTFLOAT_TEST=ON  ..  &&
           cmake --build .   &&
           ctest --output-on-failure
-      - name: Use cmake CXX20
+      - name: Use cmake CXX23
         run: |
           mkdir build20 &&
           cd build20 &&
-          CXX=g++-13 CXXFLAGS=-Werror cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DFASTFLOAT_CXX_STANDARD=20 -DFASTFLOAT_TEST=ON  ..  &&
+          CXX=g++-13 CXXFLAGS=-Werror cmake -DFASTFLOAT_CONSTEXPR_TESTS=ON -DFASTFLOAT_CXX_STANDARD=23 -DFASTFLOAT_TEST=ON  ..  &&
           cmake --build .   &&
           ctest --output-on-failure
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index da1f631..8847f06 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,7 +34,7 @@ target_include_directories(
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
     $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
 )
-target_compile_features(fast_float INTERFACE cxx_std_23)
+target_compile_features(fast_float INTERFACE cxx_std_11)
 if(FASTFLOAT_SANITIZE)
   target_compile_options(fast_float INTERFACE -fsanitize=address -fno-omit-frame-pointer -fsanitize=undefined -fno-sanitize-recover=all)
   target_link_libraries(fast_float INTERFACE -fsanitize=address -fno-omit-frame-pointer -fsanitize=undefined -fno-sanitize-recover=all)
diff --git a/include/fast_float/constexpr_feature_detect.h b/include/fast_float/constexpr_feature_detect.h
index ba8b65c..f6bd08d 100644
--- a/include/fast_float/constexpr_feature_detect.h
+++ b/include/fast_float/constexpr_feature_detect.h
@@ -8,7 +8,7 @@
 #endif
 
 // Testing for https://wg21.link/N3652, adopted in C++14
-#if __cpp_constexpr >= 201304
+#if __cpp_constexpr >= 201304`
 #define FASTFLOAT_CONSTEXPR14 constexpr
 #else
 #define FASTFLOAT_CONSTEXPR14
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index a9accc7..0739a00 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -62,10 +62,10 @@ fast_float_add_cpp_test(example_comma_test)
 fast_float_add_cpp_test(basictest)
 option(FASTFLOAT_CONSTEXPR_TESTS "Require constexpr tests (build will fail if the compiler won't support it)" OFF)
 if (FASTFLOAT_CONSTEXPR_TESTS)
-  target_compile_features(basictest PRIVATE cxx_std_23)
+  target_compile_features(basictest PRIVATE cxx_std_20)
   target_compile_definitions(basictest PRIVATE FASTFLOAT_CONSTEXPR_TESTS)
 else()
-  target_compile_features(basictest PRIVATE cxx_std_23)
+  target_compile_features(basictest PRIVATE cxx_std_17)
 endif()
 
 fast_float_add_cpp_test(long_test)