diff --git a/ide/vs2017/mimalloc.vcxproj b/ide/vs2017/mimalloc.vcxproj
index 60a1698d..426bad1b 100644
--- a/ide/vs2017/mimalloc.vcxproj
+++ b/ide/vs2017/mimalloc.vcxproj
@@ -129,7 +129,7 @@
       <ConformanceMode>true</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;MI_DEBUG=3;%(PreprocessorDefinitions);</PreprocessorDefinitions>
-      <CompileAs>CompileAsC</CompileAs>
+      <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
       <LanguageStandard>stdcpp14</LanguageStandard>
     </ClCompile>
diff --git a/ide/vs2019/mimalloc.vcxproj b/ide/vs2019/mimalloc.vcxproj
index 9f967d94..209c7cb8 100644
--- a/ide/vs2019/mimalloc.vcxproj
+++ b/ide/vs2019/mimalloc.vcxproj
@@ -114,7 +114,7 @@
       <WarningLevel>Level4</WarningLevel>
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
-      <ConformanceMode>true</ConformanceMode>
+      <ConformanceMode>Default</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>MI_DEBUG=3;%(PreprocessorDefinitions);</PreprocessorDefinitions>
       <CompileAs>CompileAsCpp</CompileAs>
diff --git a/ide/vs2022/mimalloc.vcxproj b/ide/vs2022/mimalloc.vcxproj
index 9811aa55..9c33508d 100644
--- a/ide/vs2022/mimalloc.vcxproj
+++ b/ide/vs2022/mimalloc.vcxproj
@@ -95,12 +95,12 @@
       <WarningLevel>Level4</WarningLevel>
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
-      <ConformanceMode>true</ConformanceMode>
+      <ConformanceMode>Default</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>MI_DEBUG=3;%(PreprocessorDefinitions);</PreprocessorDefinitions>
       <CompileAs>CompileAsCpp</CompileAs>
       <SupportJustMyCode>false</SupportJustMyCode>
-      <LanguageStandard>Default</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
     </ClCompile>
     <Lib>
       <AdditionalLibraryDirectories>
@@ -114,7 +114,7 @@
       <WarningLevel>Level4</WarningLevel>
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
-      <ConformanceMode>true</ConformanceMode>
+      <ConformanceMode>Default</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>MI_DEBUG=4;MI_SECURE=0;%(PreprocessorDefinitions);</PreprocessorDefinitions>
       <CompileAs>CompileAsCpp</CompileAs>
@@ -141,7 +141,7 @@
       <WarningLevel>Level4</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
-      <ConformanceMode>true</ConformanceMode>
+      <ConformanceMode>Default</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>%(PreprocessorDefinitions);NDEBUG</PreprocessorDefinitions>
       <AssemblerOutput>AssemblyAndSourceCode</AssemblerOutput>
@@ -151,7 +151,7 @@
       <InlineFunctionExpansion>Default</InlineFunctionExpansion>
       <CompileAs>CompileAsCpp</CompileAs>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <LanguageStandard>Default</LanguageStandard>
+      <LanguageStandard>stdcpp20</LanguageStandard>
     </ClCompile>
     <Link>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
@@ -169,7 +169,7 @@
       <WarningLevel>Level4</WarningLevel>
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
-      <ConformanceMode>true</ConformanceMode>
+      <ConformanceMode>Default</ConformanceMode>
       <AdditionalIncludeDirectories>../../include</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>%(PreprocessorDefinitions);NDEBUG</PreprocessorDefinitions>
       <AssemblerOutput>AssemblyAndSourceCode</AssemblerOutput>
diff --git a/include/mimalloc.h b/include/mimalloc.h
index 401c8f74..f4a43f6d 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -477,13 +477,13 @@ template<class T1,class T2> bool operator==(const mi_stl_allocator<T1>& , const
 template<class T1,class T2> bool operator!=(const mi_stl_allocator<T1>& , const mi_stl_allocator<T2>& ) mi_attr_noexcept { return false; }
 
 
-#if (__cplusplus >= 201103L) || (_MSC_VER >= 1920)  // C++11, at least vs2019
+#if (__cplusplus >= 201103L) || (_MSC_VER >= 1900)  // C++11
 #define MI_HAS_HEAP_STL_ALLOCATOR 1
 
 #include <memory>      // std::shared_ptr
 
 // Common base class for STL allocators in a specific heap
-template<class T, bool destroy> struct _mi_heap_stl_allocator_common : public _mi_stl_allocator_common<T> {
+template<class T, bool _mi_destroy> struct _mi_heap_stl_allocator_common : public _mi_stl_allocator_common<T> {
   using typename _mi_stl_allocator_common<T>::size_type;
   using typename _mi_stl_allocator_common<T>::value_type;
   using typename _mi_stl_allocator_common<T>::pointer;
@@ -502,7 +502,7 @@ template<class T, bool destroy> struct _mi_heap_stl_allocator_common : public _m
   #endif
 
   void collect(bool force) { mi_heap_collect(this->heap.get(), force); }
-  template<class U> bool is_equal(const _mi_heap_stl_allocator_common<U, destroy>& x) const { return (this->heap == x.heap); }
+  template<class U> bool is_equal(const _mi_heap_stl_allocator_common<U, _mi_destroy>& x) const { return (this->heap == x.heap); }
 
 protected:
   std::shared_ptr<mi_heap_t> heap;
@@ -510,10 +510,10 @@ protected:
   
   _mi_heap_stl_allocator_common() {
     mi_heap_t* hp = mi_heap_new();
-    this->heap.reset(hp, (destroy ? &heap_destroy : &heap_delete));  /* calls heap_delete/destroy when the refcount drops to zero */
+    this->heap.reset(hp, (_mi_destroy ? &heap_destroy : &heap_delete));  /* calls heap_delete/destroy when the refcount drops to zero */
   }
   _mi_heap_stl_allocator_common(const _mi_heap_stl_allocator_common& x) mi_attr_noexcept : heap(x.heap) { }
-  template<class U> _mi_heap_stl_allocator_common(const _mi_heap_stl_allocator_common<U, destroy>& x) mi_attr_noexcept : heap(x.heap) { }
+  template<class U> _mi_heap_stl_allocator_common(const _mi_heap_stl_allocator_common<U, _mi_destroy>& x) mi_attr_noexcept : heap(x.heap) { }
 
 private:
   static void heap_delete(mi_heap_t* hp)  { if (hp != NULL) { mi_heap_delete(hp); } }