diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2e2edc77c..a2af1a33d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -91,7 +91,7 @@ else()
   else()
     set(WARNING_FLAGS -Werror -Wall -Wno-sign-compare -Wno-unused)
   endif()
-  set(MANIFOLD_FLAGS ${MANIFOLD_FLAGS} ${WARNING_FLAGS} -fexperimental-library)
+  set(MANIFOLD_FLAGS ${MANIFOLD_FLAGS} ${WARNING_FLAGS})
 endif()
 
 if(CODE_COVERAGE AND NOT MSVC)
diff --git a/src/utilities/include/par.h b/src/utilities/include/par.h
index 4a7ed8b39..71f06a40e 100644
--- a/src/utilities/include/par.h
+++ b/src/utilities/include/par.h
@@ -24,7 +24,8 @@
 #include "thrust/transform_reduce.h"
 
 #if MANIFOLD_PAR == 'T'
-#if MANIFOLD_PAR == 'T' && TBB_INTERFACE_VERSION >= 10000 && __has_include(<execution>)
+#if MANIFOLD_PAR == 'T' && TBB_INTERFACE_VERSION >= 10000 && \
+    __has_include(<pstl/glue_execution_defs.h>)
 #include <execution>
 #endif
 
@@ -78,7 +79,7 @@ inline constexpr ExecutionPolicy autoPolicy(size_t size) {
     return thrust::NAME(thrust::cpp::par, args...);                 \
   }
 
-#if MANIFOLD_PAR == 'T' && __has_include(<execution>)
+#if MANIFOLD_PAR == 'T' && __has_include(<pstl/glue_execution_defs.h>)
 #define STL_DYNAMIC_BACKEND(NAME, RET)                        \
   template <typename Ret = RET, typename... Args>             \
   Ret NAME(ExecutionPolicy policy, Args... args) {            \
@@ -138,14 +139,15 @@ template <typename DerivedPolicy, typename InputIterator1,
 OutputIterator copy_if(ExecutionPolicy policy, InputIterator1 first,
                        InputIterator1 last, OutputIterator result,
                        Predicate pred) {
-#if MANIFOLD_PAR == 'T' && _LIBCPP_VERSION
-  if (policy == ExecutionPolicy::Seq)
-    return std::copy_if(first, last, result, pred);
-  else
-    return std::copy_if(std::execution::par_unseq, first, last, result, pred);
-#else
+  // #if MANIFOLD_PAR == 'T'
+  //   if (policy == ExecutionPolicy::Seq)
+  //     return std::copy_if(first, last, result, pred);
+  //   else
+  //     return std::copy_if(std::execution::par_unseq, first, last, result,
+  //     pred);
+  // #else
   return std::copy_if(first, last, result, pred);
-#endif
+  // #endif
 }
 
 template <typename T>
@@ -186,6 +188,8 @@ void sequence(ExecutionPolicy policy, Iterator first, Iterator last) {
 STL_DYNAMIC_BACKEND_VOID(for_each)
 STL_DYNAMIC_BACKEND_VOID(for_each_n)
 STL_DYNAMIC_BACKEND_VOID(transform)
+STL_DYNAMIC_BACKEND_VOID(uninitialized_fill)
+STL_DYNAMIC_BACKEND_VOID(uninitialized_copy)
 STL_DYNAMIC_BACKEND_VOID(stable_sort)
 STL_DYNAMIC_BACKEND_VOID(fill)
 STL_DYNAMIC_BACKEND_VOID(copy)
@@ -202,24 +206,6 @@ STL_DYNAMIC_BACKEND(all_of, bool)
 STL_DYNAMIC_BACKEND(is_sorted, bool)
 STL_DYNAMIC_BACKEND(reduce, void)
 STL_DYNAMIC_BACKEND(count_if, int)
-
-#ifdef _LIBCPP_VERSION
-template <typename... Args>
-void uninitialized_fill(ExecutionPolicy policy, Args... args) {
-  std::uninitialized_fill(args...);
-}
-template <typename... Args>
-void uninitialized_copy(ExecutionPolicy policy, Args... args) {
-  std::uninitialized_copy(args...);
-}
-template <typename Ret = void, typename... Args>
-Ret remove_if(ExecutionPolicy policy, Args... args) {
-  return std::remove_if(args...);
-}
-#else
-STL_DYNAMIC_BACKEND_VOID(uninitialized_fill)
-STL_DYNAMIC_BACKEND_VOID(uninitialized_copy)
 STL_DYNAMIC_BACKEND(remove_if, void)
-#endif
 
 }  // namespace manifold