diff --git a/libcxx/docs/Status/LFTSv3.rst b/libcxx/docs/Status/LFTSv3.rst
new file mode 100644
--- /dev/null
+++ b/libcxx/docs/Status/LFTSv3.rst
@@ -0,0 +1,31 @@
+.. lftsv3-status:
+
+========================================
+libc++ Library Fundamentals TS v3 Status
+========================================
+
+.. include:: ../Helpers/Styles.rst
+
+.. contents::
+   :local:
+
+
+Overview
+========
+
+This document contains the status of the Library Fundamentals TS v3 (LFTSv3) in libc++.
+It is used to track both the status of the sub-projects and who is assigned to
+these sub-projects. This is imperative to effective implementation so that work
+is not duplicated and implementors are not blocked by each other.
+
+If you are interested in contributing to the libc++ LFTSv3, please send
+a message to the #libcxx channel in the LLVM discord. Please *do not* start
+working on any of the assigned items below.
+
+Sub-Projects in the Format library
+==================================
+
+.. csv-table::
+   :file: FormatPaper.csv
+   :header-rows: 1
+   :widths: auto
diff --git a/libcxx/docs/Status/LFTSv3Paper.csv b/libcxx/docs/Status/LFTSv3Paper.csv
new file mode 100644
--- /dev/null
+++ b/libcxx/docs/Status/LFTSv3Paper.csv
@@ -0,0 +1,10 @@
+Section,Description,Dependencies,Status
+`[utilities] <https://wg21.link/N4920>`_,"",,Not assigned,|Complete|
+`[propagate_const] <https://wg21.link/N4920>`_,"",,,|Complete|
+`[meta] <https://wg21.link/N4920>`_,"",,Not assigned,|Partial|
+`[func] <https://wg21.link/N4920>`_,"",,Not assigned,|Not Started|
+`[memory] <https://wg21.link/N4920>`_,"",,Not assigned,|Not Started|
+`[iterator] <https://wg21.link/N4920>`_,"",,,|Complete|
+`[futures] <https://wg21.link/N4920>`_,"",,Not assigned,|Not Started|
+`[algorithms] <https://wg21.link/N4920>`_,"",,Not assigned,|Not Started|
+`[numeric] <https://wg21.link/N4920>`_,"",,Not assigned,|Not Started|
diff --git a/libcxx/include/experimental/__config b/libcxx/include/experimental/__config
--- a/libcxx/include/experimental/__config
+++ b/libcxx/include/experimental/__config
@@ -20,17 +20,19 @@
 #define _LIBCPP_END_NAMESPACE_EXPERIMENTAL  } }
 #define _VSTD_EXPERIMENTAL std::experimental
 
-#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
+#if _LIBCPP_STD_VER <= 17
+#define _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20(symbol) _LIBCPP_DEPRECATED_("The library fundamentals TS is now based on C++20. " symbol " will only be available in C++20 in LLVM 19.")
+#else
+#define _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20(symbol)
+#endif
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v3 {
 #define _LIBCPP_END_NAMESPACE_LFTS  } } }
-#define _VSTD_LFTS _VSTD_EXPERIMENTAL::fundamentals_v1
+#define _VSTD_LFTS _VSTD_EXPERIMENTAL::fundamentals_v3
 
-#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v3 {
 #define _LIBCPP_END_NAMESPACE_LFTS_V2  } } }
-#define _VSTD_LFTS_V2 _VSTD_EXPERIMENTAL::fundamentals_v2
-
-#define _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR _LIBCPP_BEGIN_NAMESPACE_LFTS namespace pmr {
-#define _LIBCPP_END_NAMESPACE_LFTS_PMR _LIBCPP_END_NAMESPACE_LFTS }
-#define _VSTD_LFTS_PMR _VSTD_LFTS::pmr
+#define _VSTD_LFTS_V2 _VSTD_EXPERIMENTAL::fundamentals_v3
 
 #define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD \
     _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace parallelism_v2 {
diff --git a/libcxx/include/experimental/__memory b/libcxx/include/experimental/__memory
deleted file mode 100644
--- a/libcxx/include/experimental/__memory
+++ /dev/null
@@ -1,120 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL___MEMORY
-#define _LIBCPP_EXPERIMENTAL___MEMORY
-
-#include <__memory/allocator_arg_t.h>
-#include <__memory/uses_allocator.h>
-#include <__type_traits/conditional.h>
-#include <__type_traits/is_constructible.h>
-#include <__type_traits/is_convertible.h>
-#include <__type_traits/is_same.h>
-#include <experimental/__config>
-#include <experimental/utility> // for erased_type
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS
-
-template <
-    class _Tp, class _Alloc
-  , bool = uses_allocator<_Tp, _Alloc>::value
-  , bool = __has_allocator_type<_Tp>::value
-  >
-struct __lfts_uses_allocator : public false_type {};
-
-template <class _Tp, class _Alloc>
-struct __lfts_uses_allocator<_Tp, _Alloc, false, false> : public false_type {};
-
-template <class _Tp, class _Alloc, bool HasAlloc>
-struct __lfts_uses_allocator<_Tp, _Alloc, true, HasAlloc> : public true_type {};
-
-template <class _Tp, class _Alloc>
-struct __lfts_uses_allocator<_Tp, _Alloc, false, true>
-  : public integral_constant<bool
-    , is_convertible<_Alloc, typename _Tp::allocator_type>::value
-      || is_same<erased_type, typename _Tp::allocator_type>::value
-    >
-{};
-
-template <bool _UsesAlloc, class _Tp, class _Alloc, class ..._Args>
-struct __lfts_uses_alloc_ctor_imp
-{
-    static const int value = 0;
-};
-
-template <class _Tp, class _Alloc, class ..._Args>
-struct __lfts_uses_alloc_ctor_imp<true, _Tp, _Alloc, _Args...>
-{
-    static const bool __ic_first
-        = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
-
-    static const bool __ic_second =
-        __conditional_t<
-            __ic_first,
-            false_type,
-            is_constructible<_Tp, _Args..., _Alloc>
-        >::value;
-
-    static_assert(__ic_first || __ic_second,
-                  "Request for uses allocator construction is ill-formed");
-
-    static const int value = __ic_first ? 1 : 2;
-};
-
-template <class _Tp, class _Alloc, class ..._Args>
-struct __lfts_uses_alloc_ctor
-  : integral_constant<int,
-        __lfts_uses_alloc_ctor_imp<
-            __lfts_uses_allocator<_Tp, _Alloc>::value
-          , _Tp, _Alloc, _Args...
-        >::value
-    >
-{};
-
-template <class _Tp, class _Allocator, class... _Args>
-inline _LIBCPP_INLINE_VISIBILITY
-void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
-{
-    new (__storage) _Tp (_VSTD::forward<_Args>(__args)...);
-}
-
-// FIXME: This should have a version which takes a non-const alloc.
-template <class _Tp, class _Allocator, class... _Args>
-inline _LIBCPP_INLINE_VISIBILITY
-void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
-{
-    new (__storage) _Tp (allocator_arg_t(), __a, _VSTD::forward<_Args>(__args)...);
-}
-
-// FIXME: This should have a version which takes a non-const alloc.
-template <class _Tp, class _Allocator, class... _Args>
-inline _LIBCPP_INLINE_VISIBILITY
-void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
-{
-    new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a);
-}
-
-template <class _Tp, class _Alloc, class ..._Args>
-inline _LIBCPP_INLINE_VISIBILITY
-void __lfts_user_alloc_construct(
-    _Tp * __store, const _Alloc & __a, _Args &&... __args)
-{
-    ::std::experimental::fundamentals_v1::__user_alloc_construct_impl(
-        typename __lfts_uses_alloc_ctor<_Tp, _Alloc, _Args...>::type()
-       , __store, __a, _VSTD::forward<_Args>(__args)...
-       );
-}
-
-_LIBCPP_END_NAMESPACE_LFTS
-
-#endif /* _LIBCPP_EXPERIMENTAL___MEMORY */
diff --git a/libcxx/include/experimental/deque b/libcxx/include/experimental/deque
deleted file mode 100644
--- a/libcxx/include/experimental/deque
+++ /dev/null
@@ -1,52 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_DEQUE
-#define _LIBCPP_EXPERIMENTAL_DEQUE
-
-/*
-    experimental/deque synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class T>
-  using deque = std::deque<T,polymorphic_allocator<T>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <deque>
-#include <experimental/__config>
-#include <experimental/memory_resource>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _ValueT>
-using deque = _VSTD::deque<_ValueT, polymorphic_allocator<_ValueT>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_DEQUE */
diff --git a/libcxx/include/experimental/forward_list b/libcxx/include/experimental/forward_list
deleted file mode 100644
--- a/libcxx/include/experimental/forward_list
+++ /dev/null
@@ -1,52 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_FORWARD_LIST
-#define _LIBCPP_EXPERIMENTAL_FORWARD_LIST
-
-/*
-    experimental/forward_list synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class T>
-  using forward_list = std::forward_list<T,polymorphic_allocator<T>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <forward_list>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _ValueT>
-using forward_list = _VSTD::forward_list<_ValueT, polymorphic_allocator<_ValueT>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_FORWARD_LIST */
diff --git a/libcxx/include/experimental/iterator b/libcxx/include/experimental/iterator
--- a/libcxx/include/experimental/iterator
+++ b/libcxx/include/experimental/iterator
@@ -70,7 +70,7 @@
 _LIBCPP_BEGIN_NAMESPACE_LFTS
 
 template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
-class ostream_joiner {
+class _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("ostream_joiner") ostream_joiner {
 public:
 
     typedef _CharT                               char_type;
@@ -111,6 +111,7 @@
 
 
 template <class _CharT, class _Traits, class _Delim>
+_LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("make_ostream_joiner")
 _LIBCPP_HIDE_FROM_ABI ostream_joiner<__decay_t<_Delim>, _CharT, _Traits>
 make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os, _Delim && __d)
 { return ostream_joiner<__decay_t<_Delim>, _CharT, _Traits>(__os, _VSTD::forward<_Delim>(__d)); }
diff --git a/libcxx/include/experimental/list b/libcxx/include/experimental/list
deleted file mode 100644
--- a/libcxx/include/experimental/list
+++ /dev/null
@@ -1,52 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_LIST
-#define _LIBCPP_EXPERIMENTAL_LIST
-
-/*
-    experimental/list synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class T>
-  using list = std::list<T,polymorphic_allocator<T>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <list>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _ValueT>
-using list = _VSTD::list<_ValueT, polymorphic_allocator<_ValueT>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_LIST */
diff --git a/libcxx/include/experimental/map b/libcxx/include/experimental/map
deleted file mode 100644
--- a/libcxx/include/experimental/map
+++ /dev/null
@@ -1,62 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_MAP
-#define _LIBCPP_EXPERIMENTAL_MAP
-
-/*
-    experimental/map synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class Key, class T, class Compare = less<Key>>
-  using map = std::map<Key, T, Compare,
-                       polymorphic_allocator<pair<const Key,T>>>;
-
-  template <class Key, class T, class Compare = less<Key>>
-  using multimap = std::multimap<Key, T, Compare,
-                                 polymorphic_allocator<pair<const Key,T>>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <map>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _Key, class _Value, class  _Compare = less<_Key>>
-using map = _VSTD::map<_Key, _Value, _Compare,
-                        polymorphic_allocator<pair<const _Key, _Value>>>;
-
-template <class _Key, class _Value, class  _Compare = less<_Key>>
-using multimap = _VSTD::multimap<_Key, _Value, _Compare,
-                        polymorphic_allocator<pair<const _Key, _Value>>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_MAP */
diff --git a/libcxx/include/experimental/memory_resource b/libcxx/include/experimental/memory_resource
--- a/libcxx/include/experimental/memory_resource
+++ b/libcxx/include/experimental/memory_resource
@@ -20,22 +20,6 @@
 inline namespace fundamentals_v1 {
 namespace pmr {
 
-  class memory_resource;
-
-  bool operator==(const memory_resource& a,
-                  const memory_resource& b) noexcept;
-  bool operator!=(const memory_resource& a,
-                  const memory_resource& b) noexcept;
-
-  template <class Tp> class polymorphic_allocator;
-
-  template <class T1, class T2>
-  bool operator==(const polymorphic_allocator<T1>& a,
-                  const polymorphic_allocator<T2>& b) noexcept;
-  template <class T1, class T2>
-  bool operator!=(const polymorphic_allocator<T1>& a,
-                  const polymorphic_allocator<T2>& b) noexcept;
-
   // The name resource_adaptor_imp is for exposition only.
   template <class Allocator> class resource_adaptor_imp;
 
@@ -43,20 +27,6 @@
     using resource_adaptor = resource_adaptor_imp<
       allocator_traits<Allocator>::rebind_alloc<char>>;
 
-  // Global memory resources
-  memory_resource* new_delete_resource() noexcept;
-  memory_resource* null_memory_resource() noexcept;
-
-  // The default memory resource
-  memory_resource* set_default_resource(memory_resource* r) noexcept;
-  memory_resource* get_default_resource() noexcept;
-
-  // Standard memory resources
-  struct pool_options;
-  class synchronized_pool_resource;
-  class unsynchronized_pool_resource;
-  class monotonic_buffer_resource;
-
 } // namespace pmr
 } // namespace fundamentals_v1
 } // namespace experimental
@@ -70,8 +40,8 @@
 #include <__utility/move.h>
 #include <cstddef>
 #include <experimental/__config>
-#include <experimental/__memory>
 #include <limits>
+#include <memory_resource>
 #include <new>
 #include <stdexcept>
 #include <tuple>
@@ -83,13 +53,9 @@
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+namespace std::experimental::inline fundamentals_v3::pmr {
 
-#define _LIBCPP_DEPCREATED_MEMORY_RESOURCE(name)                                                                       \
-  _LIBCPP_DEPRECATED_("'std::experimental::pmr::" name                                                                 \
-                      "' is deprecated and will be removed in LLVM 18. Use 'std::pmr::" name "' instead.")
-
-#ifndef _LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER >= 20
 
 // Round __s up to next multiple of __a.
 inline _LIBCPP_INLINE_VISIBILITY
@@ -99,250 +65,13 @@
     return (__s + __a - 1) & ~(__a - 1);
 }
 
-// 8.5, memory.resource
-class _LIBCPP_DEPCREATED_MEMORY_RESOURCE("memory_resource") _LIBCPP_EXPORTED_FROM_ABI memory_resource
-{
-    static const size_t __max_align = _LIBCPP_ALIGNOF(max_align_t);
-
-// 8.5.2, memory.resource.public
-public:
-    _LIBCPP_HIDE_FROM_ABI_VIRTUAL virtual ~memory_resource() = default;
-
-    _LIBCPP_INLINE_VISIBILITY
-    void* allocate(size_t __bytes, size_t __align = __max_align)
-        { return do_allocate(__bytes, __align); }
-
-    _LIBCPP_INLINE_VISIBILITY
-    void deallocate(void * __p, size_t __bytes, size_t __align = __max_align)
-        { do_deallocate(__p, __bytes, __align); }
-
-    _LIBCPP_INLINE_VISIBILITY
-    bool is_equal(memory_resource const & __other) const _NOEXCEPT
-        { return do_is_equal(__other); }
-
-// 8.5.3, memory.resource.priv
-private:
-    virtual void* do_allocate(size_t, size_t) = 0;
-    virtual void do_deallocate(void*, size_t, size_t) = 0;
-    virtual bool do_is_equal(memory_resource const &) const _NOEXCEPT = 0;
-};
-
-// 8.5.4, memory.resource.eq
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("operator==(memory_resource, memory_resource)") inline _LIBCPP_INLINE_VISIBILITY
-bool operator==(memory_resource const & __lhs,
-                memory_resource const & __rhs) _NOEXCEPT
-{
-    return &__lhs == &__rhs || __lhs.is_equal(__rhs);
-}
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("operator!=(memory_resource, memory_resource)") inline _LIBCPP_INLINE_VISIBILITY
-bool operator!=(memory_resource const & __lhs,
-                memory_resource const & __rhs) _NOEXCEPT
-{
-    return !(__lhs == __rhs);
-}
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("new_delete_resource()") _LIBCPP_EXPORTED_FROM_ABI
-memory_resource * new_delete_resource() _NOEXCEPT;
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("null_memory_resource()") _LIBCPP_EXPORTED_FROM_ABI
-memory_resource * null_memory_resource() _NOEXCEPT;
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("get_default_resource()") _LIBCPP_EXPORTED_FROM_ABI
-memory_resource * get_default_resource() _NOEXCEPT;
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("set_default_resource()") _LIBCPP_EXPORTED_FROM_ABI
-memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT;
-
-// 8.6, memory.polymorphic.allocator.class
-
-// 8.6.1, memory.polymorphic.allocator.overview
-template <class _ValueType>
-class _LIBCPP_DEPCREATED_MEMORY_RESOURCE("polymorphic_allocator") _LIBCPP_TEMPLATE_VIS polymorphic_allocator
-{
-public:
-    typedef _ValueType value_type;
-
-    // 8.6.2, memory.polymorphic.allocator.ctor
-    _LIBCPP_INLINE_VISIBILITY
-    polymorphic_allocator() _NOEXCEPT
-      : __res_(_VSTD_LFTS_PMR::get_default_resource())
-    {}
-
-    _LIBCPP_INLINE_VISIBILITY
-    polymorphic_allocator(memory_resource * __r) _NOEXCEPT
-      : __res_(__r)
-    {}
-
-    _LIBCPP_HIDE_FROM_ABI polymorphic_allocator(polymorphic_allocator const &) = default;
-
-    template <class _Tp>
-    _LIBCPP_INLINE_VISIBILITY
-    polymorphic_allocator(polymorphic_allocator<_Tp> const & __other) _NOEXCEPT
-      : __res_(__other.resource())
-    {}
-
-    polymorphic_allocator &
-    operator=(polymorphic_allocator const &) = delete;
-
-    // 8.6.3, memory.polymorphic.allocator.mem
-    _LIBCPP_INLINE_VISIBILITY
-    _ValueType* allocate(size_t __n) {
-        if (__n > __max_size())
-            __throw_bad_array_new_length();
-        return static_cast<_ValueType*>(
-            __res_->allocate(__n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType))
-        );
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    void deallocate(_ValueType * __p, size_t __n) _NOEXCEPT {
-        _LIBCPP_ASSERT_UNCATEGORIZED(__n <= __max_size(),
-                                     "deallocate called for size which exceeds max_size()");
-        __res_->deallocate(__p, __n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType));
-    }
-
-    template <class _Tp, class ..._Ts>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(_Tp* __p, _Ts &&... __args)
-    {
-        _VSTD_LFTS::__lfts_user_alloc_construct(
-            __p, *this, _VSTD::forward<_Ts>(__args)...
-          );
-    }
-
-    template <class _T1, class _T2, class ..._Args1, class ..._Args2>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(pair<_T1, _T2>* __p, piecewise_construct_t,
-                   tuple<_Args1...> __x, tuple<_Args2...> __y)
-    {
-        ::new ((void*)__p) pair<_T1, _T2>(piecewise_construct
-          , __transform_tuple(
-              typename __lfts_uses_alloc_ctor<
-                  _T1, polymorphic_allocator&, _Args1...
-              >::type()
-            , _VSTD::move(__x)
-            , typename __make_tuple_indices<sizeof...(_Args1)>::type{}
-          )
-          , __transform_tuple(
-              typename __lfts_uses_alloc_ctor<
-                  _T2, polymorphic_allocator&, _Args2...
-              >::type()
-            , _VSTD::move(__y)
-            , typename __make_tuple_indices<sizeof...(_Args2)>::type{}
-          )
-        );
-    }
-
-    template <class _T1, class _T2>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(pair<_T1, _T2>* __p) {
-        construct(__p, piecewise_construct, tuple<>(), tuple<>());
-    }
-
-    template <class _T1, class _T2, class _Up, class _Vp>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(pair<_T1, _T2> * __p, _Up && __u, _Vp && __v) {
-        construct(__p, piecewise_construct
-          , _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__u))
-          , _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__v)));
-    }
-
-    template <class _T1, class _T2, class _U1, class _U2>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> const & __pr) {
-        construct(__p, piecewise_construct
-            , _VSTD::forward_as_tuple(__pr.first)
-            , _VSTD::forward_as_tuple(__pr.second));
-    }
-
-    template <class _T1, class _T2, class _U1, class _U2>
-    _LIBCPP_INLINE_VISIBILITY
-    void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> && __pr){
-        construct(__p, piecewise_construct
-            , _VSTD::forward_as_tuple(_VSTD::forward<_U1>(__pr.first))
-            , _VSTD::forward_as_tuple(_VSTD::forward<_U2>(__pr.second)));
-    }
-
-    template <class _Tp>
-    _LIBCPP_INLINE_VISIBILITY
-    void destroy(_Tp * __p) _NOEXCEPT
-        { __p->~_Tp(); }
-
-    _LIBCPP_INLINE_VISIBILITY
-    polymorphic_allocator
-    select_on_container_copy_construction() const _NOEXCEPT
-        { return polymorphic_allocator(); }
-
-    _LIBCPP_INLINE_VISIBILITY
-    memory_resource * resource() const _NOEXCEPT
-        { return __res_; }
-
-private:
-    template <class ..._Args, size_t ..._Idx>
-    _LIBCPP_INLINE_VISIBILITY
-    tuple<_Args&&...>
-    __transform_tuple(integral_constant<int, 0>, tuple<_Args...>&& __t,
-                      __tuple_indices<_Idx...>) const
-    {
-        return _VSTD::forward_as_tuple(_VSTD::get<_Idx>(_VSTD::move(__t))...);
-    }
-
-    template <class ..._Args, size_t ..._Idx>
-    _LIBCPP_INLINE_VISIBILITY
-    tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>
-    __transform_tuple(integral_constant<int, 1>, tuple<_Args...> && __t,
-                      __tuple_indices<_Idx...>)
-    {
-        using _Tup = tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>;
-        return _Tup(allocator_arg, *this,
-                    _VSTD::get<_Idx>(_VSTD::move(__t))...);
-    }
-
-    template <class ..._Args, size_t ..._Idx>
-    _LIBCPP_INLINE_VISIBILITY
-    tuple<_Args&&..., polymorphic_allocator&>
-    __transform_tuple(integral_constant<int, 2>, tuple<_Args...> && __t,
-                      __tuple_indices<_Idx...>)
-    {
-        using _Tup = tuple<_Args&&..., polymorphic_allocator&>;
-        return _Tup(_VSTD::get<_Idx>(_VSTD::move(__t))..., *this);
-    }
-
-    _LIBCPP_INLINE_VISIBILITY
-    size_t __max_size() const _NOEXCEPT
-        { return numeric_limits<size_t>::max() / sizeof(value_type); }
-
-    memory_resource * __res_;
-};
-
-// 8.6.4, memory.polymorphic.allocator.eq
-
-template <class _Tp, class _Up>
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("operator==(const polymorphic_allocator&, const polymorphic_allocator&)")
-inline _LIBCPP_INLINE_VISIBILITY
-bool operator==(polymorphic_allocator<_Tp> const & __lhs,
-                polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
-{
-    return *__lhs.resource() == *__rhs.resource();
-}
-
-template <class _Tp, class _Up>
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("operator!=(const polymorphic_allocator&, const polymorphic_allocator&)")
-inline _LIBCPP_INLINE_VISIBILITY
-bool operator!=(polymorphic_allocator<_Tp> const & __lhs,
-                polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
-{
-    return !(__lhs == __rhs);
-}
-
 // 8.7, memory.resource.adaptor
 
 _LIBCPP_SUPPRESS_DEPRECATED_PUSH
 // 8.7.1, memory.resource.adaptor.overview
 template <class _CharAlloc>
 class _LIBCPP_TEMPLATE_VIS __resource_adaptor_imp
-  : public memory_resource
+  : public std::pmr::memory_resource
 {
     using _CTraits = allocator_traits<_CharAlloc>;
     static_assert(is_same<typename _CTraits::value_type, char>::value
@@ -421,9 +150,9 @@
   >;
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
-#endif // _LIBCPP_CXX03_LANG
+#endif // _LIBCPP_STD_VER >= 20
 
-_LIBCPP_END_NAMESPACE_LFTS_PMR
+} // namespace std::experimental::fundamentals_v3::pmr
 
 _LIBCPP_POP_MACROS
 
diff --git a/libcxx/include/experimental/propagate_const b/libcxx/include/experimental/propagate_const
--- a/libcxx/include/experimental/propagate_const
+++ b/libcxx/include/experimental/propagate_const
@@ -154,7 +154,7 @@
 _Up& get_underlying(propagate_const<_Up>& __pu) _NOEXCEPT;
 
 template <class _Tp>
-class propagate_const
+class _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("propagate_const") propagate_const
 {
 public:
   typedef remove_reference_t<decltype(*std::declval<_Tp&>())> element_type;
@@ -504,90 +504,90 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-struct hash<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct hash<experimental::propagate_const<_Tp>>
 {
   typedef size_t result_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> argument_type;
+  typedef experimental::propagate_const<_Tp> argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI size_t operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1) const
+  _LIBCPP_HIDE_FROM_ABI size_t operator()(const experimental::propagate_const<_Tp>& __pc1) const
   {
     return std::hash<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1));
   }
 };
 
 template <class _Tp>
-struct equal_to<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct equal_to<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::equal_to<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
 };
 
 template <class _Tp>
-struct not_equal_to<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct not_equal_to<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::not_equal_to<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
 };
 
 template <class _Tp>
-struct less<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct less<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::less<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
 };
 
 template <class _Tp>
-struct greater<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct greater<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::greater<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
 };
 
 template <class _Tp>
-struct less_equal<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct less_equal<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::less_equal<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
 };
 
 template <class _Tp>
-struct greater_equal<experimental::fundamentals_v2::propagate_const<_Tp>>
+struct greater_equal<experimental::propagate_const<_Tp>>
 {
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
-  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+  typedef experimental::propagate_const<_Tp> first_argument_type;
+  typedef experimental::propagate_const<_Tp> second_argument_type;
 
-  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
-      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  _LIBCPP_HIDE_FROM_ABI bool operator()(const experimental::propagate_const<_Tp>& __pc1,
+      const experimental::propagate_const<_Tp>& __pc2) const
   {
     return std::greater_equal<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
   }
diff --git a/libcxx/include/experimental/regex b/libcxx/include/experimental/regex
deleted file mode 100644
--- a/libcxx/include/experimental/regex
+++ /dev/null
@@ -1,69 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_REGEX
-#define _LIBCPP_EXPERIMENTAL_REGEX
-
-/*
-    experimental/regex synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class BidirectionalIterator>
-  using match_results =
-    std::match_results<BidirectionalIterator,
-                       polymorphic_allocator<sub_match<BidirectionalIterator>>>;
-
-  typedef match_results<const char*> cmatch;
-  typedef match_results<const wchar_t*> wcmatch;
-  typedef match_results<string::const_iterator> smatch;
-  typedef match_results<wstring::const_iterator> wsmatch;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <experimental/string>
-#include <regex>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _BiDirIter>
-using match_results =
-    _VSTD::match_results<_BiDirIter,
-        polymorphic_allocator<_VSTD::sub_match<_BiDirIter>>>;
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("cmatch") typedef match_results<const char*> cmatch;
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("smatch") typedef match_results<_VSTD_LFTS_PMR::string::const_iterator> smatch;
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("wcmatch") typedef match_results<const wchar_t*> wcmatch;
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("wsmatch") typedef match_results<_VSTD_LFTS_PMR::wstring::const_iterator> wsmatch;
-#endif
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_REGEX */
diff --git a/libcxx/include/experimental/set b/libcxx/include/experimental/set
deleted file mode 100644
--- a/libcxx/include/experimental/set
+++ /dev/null
@@ -1,62 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_SET
-#define _LIBCPP_EXPERIMENTAL_SET
-
-/*
-    experimental/set synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class Key, class T, class Compare = less<Key>>
-  using set = std::set<Key, T, Compare,
-                       polymorphic_allocator<pair<const Key,T>>>;
-
-  template <class Key, class T, class Compare = less<Key>>
-  using multiset = std::multiset<Key, T, Compare,
-                                 polymorphic_allocator<pair<const Key,T>>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <set>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _Value, class  _Compare = less<_Value>>
-using set = _VSTD::set<_Value, _Compare,
-                        polymorphic_allocator<_Value>>;
-
-template <class _Value, class  _Compare = less<_Value>>
-using multiset = _VSTD::multiset<_Value, _Compare,
-                        polymorphic_allocator<_Value>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_SET */
diff --git a/libcxx/include/experimental/string b/libcxx/include/experimental/string
deleted file mode 100644
--- a/libcxx/include/experimental/string
+++ /dev/null
@@ -1,73 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_STRING
-#define _LIBCPP_EXPERIMENTAL_STRING
-
-/*
-    experimental/string synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  // basic_string using polymorphic allocator in namespace pmr
-  template <class charT, class traits = char_traits<charT>>
-   using basic_string =
-     std::basic_string<charT, traits, polymorphic_allocator<charT>>;
-
-  // basic_string typedef names using polymorphic allocator in namespace
-  // std::experimental::pmr
-  typedef basic_string<char> string;
-  typedef basic_string<char16_t> u16string;
-  typedef basic_string<char32_t> u32string;
-  typedef basic_string<wchar_t> wstring;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <string>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-
-template <class _CharT, class _Traits = char_traits<_CharT>>
-using basic_string =
-    _VSTD::basic_string<_CharT, _Traits, polymorphic_allocator<_CharT>>;
-
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("string") typedef basic_string<char> string;
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("u16string") typedef basic_string<char16_t> u16string;
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("u32string") typedef basic_string<char32_t> u32string;
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
-_LIBCPP_DEPCREATED_MEMORY_RESOURCE("wstring") typedef basic_string<wchar_t> wstring;
-#endif
-
-_LIBCPP_SUPPRESS_DEPRECATED_POP
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_STRING */
diff --git a/libcxx/include/experimental/type_traits b/libcxx/include/experimental/type_traits
--- a/libcxx/include/experimental/type_traits
+++ b/libcxx/include/experimental/type_traits
@@ -103,10 +103,7 @@
 using raw_invocation_type_t = typename raw_invocation_type<_Tp>::type;
 */
 
-// 3.3.4, Detection idiom
-template <class...> using void_t = void;
-
-struct nonesuch : private __nat { // make nonesuch "not an aggregate"
+struct _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("nonesuch") nonesuch : private __nat { // make nonesuch "not an aggregate"
   ~nonesuch() = delete;
   nonesuch      (nonesuch const&) = delete;
   void operator=(nonesuch const&) = delete;
@@ -130,7 +127,7 @@
 template <template<class...> class _Op, class... _Args>
   using detected_t = typename _DETECTOR<nonesuch, void, _Op, _Args...>::type;
 template <template<class...> class _Op, class... _Args>
-  _LIBCPP_CONSTEXPR bool is_detected_v = is_detected<_Op, _Args...>::value;
+  _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("is_detected_v") _LIBCPP_CONSTEXPR bool is_detected_v = is_detected<_Op, _Args...>::value;
 
 template <class _Default, template<class...> class _Op, class... _Args>
   using detected_or = _DETECTOR<_Default, void, _Op, _Args...>;
@@ -140,12 +137,12 @@
 template <class _Expected, template<class...> class _Op, class... _Args>
   using is_detected_exact = is_same<_Expected, detected_t<_Op, _Args...>>;
 template <class _Expected, template<class...> class _Op, class... _Args>
-  _LIBCPP_CONSTEXPR bool is_detected_exact_v = is_detected_exact<_Expected, _Op, _Args...>::value;
+  _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("is_detected_exact_v") _LIBCPP_CONSTEXPR bool is_detected_exact_v = is_detected_exact<_Expected, _Op, _Args...>::value;
 
 template <class _To, template<class...> class _Op, class... _Args>
   using is_detected_convertible = is_convertible<detected_t<_Op, _Args...>, _To>;
 template <class _To, template<class...> class _Op, class... _Args>
-  _LIBCPP_CONSTEXPR bool is_detected_convertible_v = is_detected_convertible<_To, _Op, _Args...>::value;
+  _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("is_detected_convertible_v") _LIBCPP_CONSTEXPR bool is_detected_convertible_v = is_detected_convertible<_To, _Op, _Args...>::value;
 
 
 _LIBCPP_END_NAMESPACE_LFTS
diff --git a/libcxx/include/experimental/unordered_map b/libcxx/include/experimental/unordered_map
deleted file mode 100644
--- a/libcxx/include/experimental/unordered_map
+++ /dev/null
@@ -1,78 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_UNORDERED_MAP
-#define _LIBCPP_EXPERIMENTAL_UNORDERED_MAP
-
-/*
-    experimental/unordered_map synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class Key, class T,
-            class Hash = hash<Key>,
-            class Pred = equal_to<Key>>
-  using unordered_map =
-    std::unordered_map<Key, T, Hash, Pred,
-                       polymorphic_allocator<pair<const Key,T>>>;
-
-  template <class Key, class T,
-            class Hash = hash<Key>,
-            class Pred = equal_to<Key>>
-  using unordered_multimap =
-    std::unordered_multimap<Key, T, Hash, Pred,
-                            polymorphic_allocator<pair<const Key,T>>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <unordered_map>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _Key, class _Value,
-          class _Hash = hash<_Key>, class _Pred = equal_to<_Key>>
-using unordered_map = _VSTD::unordered_map<_Key, _Value, _Hash, _Pred,
-                        polymorphic_allocator<pair<const _Key, _Value>>>;
-
-template <class _Key, class _Value,
-          class _Hash = hash<_Key>, class _Pred = equal_to<_Key>>
-using unordered_multimap = _VSTD::unordered_multimap<_Key, _Value, _Hash, _Pred,
-                        polymorphic_allocator<pair<const _Key, _Value>>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
-#  include <algorithm>
-#  include <array>
-#  include <bit>
-#  include <functional>
-#  include <vector>
-#endif
-
-#endif /* _LIBCPP_EXPERIMENTAL_UNORDERED_MAP */
diff --git a/libcxx/include/experimental/unordered_set b/libcxx/include/experimental/unordered_set
deleted file mode 100644
--- a/libcxx/include/experimental/unordered_set
+++ /dev/null
@@ -1,64 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_UNORDERED_SET
-#define _LIBCPP_EXPERIMENTAL_UNORDERED_SET
-
-/*
-    experimental/unordered_set synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class T, class Hash = hash<T>, class Pred = equal_to<T>>
-  using unordered_set = std::unordered_set<T, Hash, Pred,
-                       polymorphic_allocator<T>>;
-
-  template <class T, class Hash = hash<T>, class Pred = equal_to<T>>
-  using unordered_multiset = std::unordered_multiset<T, Hash, Pred,
-                       polymorphic_allocator<T>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <unordered_set>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _Value,
-          class _Hash = hash<_Value>, class _Pred = equal_to<_Value>>
-using unordered_set = _VSTD::unordered_set<_Value, _Hash, _Pred,
-                        polymorphic_allocator<_Value>>;
-
-template <class _Value,
-          class _Hash = hash<_Value>, class _Pred = equal_to<_Value>>
-using unordered_multiset = _VSTD::unordered_multiset<_Value, _Hash, _Pred,
-                        polymorphic_allocator<_Value>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_UNORDERED_SET */
diff --git a/libcxx/include/experimental/utility b/libcxx/include/experimental/utility
--- a/libcxx/include/experimental/utility
+++ b/libcxx/include/experimental/utility
@@ -40,7 +40,7 @@
 
 _LIBCPP_BEGIN_NAMESPACE_LFTS
 
-  struct _LIBCPP_TEMPLATE_VIS erased_type { };
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_LFTS_IS_NOW_CXX20("erased_type") erased_type { };
 
 _LIBCPP_END_NAMESPACE_LFTS
 
diff --git a/libcxx/include/experimental/vector b/libcxx/include/experimental/vector
deleted file mode 100644
--- a/libcxx/include/experimental/vector
+++ /dev/null
@@ -1,52 +0,0 @@
-// -*- C++ -*-
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXPERIMENTAL_VECTOR
-#define _LIBCPP_EXPERIMENTAL_VECTOR
-
-/*
-    experimental/vector synopsis
-
-// C++1z
-namespace std {
-namespace experimental {
-inline namespace fundamentals_v1 {
-namespace pmr {
-
-  template <class T>
-  using vector = std::vector<T, polymorphic_allocator<T>>;
-
-} // namespace pmr
-} // namespace fundamentals_v1
-} // namespace experimental
-} // namespace std
-
- */
-
-#include <__assert> // all public C++ headers provide the assertion handler
-#include <experimental/__config>
-#include <experimental/memory_resource>
-#include <vector>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-#ifndef _LIBCPP_CXX03_LANG
-
-template <class _ValueT>
-using vector = _VSTD::vector<_ValueT, polymorphic_allocator<_ValueT>>;
-
-#endif // _LIBCPP_CXX03_LANG
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
-
-#endif /* _LIBCPP_EXPERIMENTAL_VECTOR */
diff --git a/libcxx/src/experimental/memory_resource.cpp b/libcxx/src/experimental/memory_resource.cpp
deleted file mode 100644
--- a/libcxx/src/experimental/memory_resource.cpp
+++ /dev/null
@@ -1,149 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include <experimental/memory_resource>
-
-_LIBCPP_SUPPRESS_DEPRECATED_PUSH
-
-#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
-#  include <atomic>
-#elif !defined(_LIBCPP_HAS_NO_THREADS)
-#  include <mutex>
-#  if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
-#    pragma comment(lib, "pthread")
-#  endif
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
-
-// memory_resource
-
-//memory_resource::~memory_resource() {}
-
-// new_delete_resource()
-
-class _LIBCPP_EXPORTED_FROM_ABI __new_delete_memory_resource_imp
-    : public memory_resource
-{
-    void *do_allocate(size_t size, size_t align) override {
-#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
-        if (__is_overaligned_for_new(align))
-            __throw_bad_alloc();
-#endif
-        return _VSTD::__libcpp_allocate(size, align);
-    }
-
-    void do_deallocate(void *p, size_t n, size_t align) override {
-      _VSTD::__libcpp_deallocate(p, n, align);
-    }
-
-    bool do_is_equal(memory_resource const & other) const noexcept override
-        { return &other == this; }
-
-public:
-    ~__new_delete_memory_resource_imp() override = default;
-};
-
-// null_memory_resource()
-
-class _LIBCPP_EXPORTED_FROM_ABI __null_memory_resource_imp
-    : public memory_resource
-{
-public:
-    ~__null_memory_resource_imp() = default;
-
-protected:
-    virtual void* do_allocate(size_t, size_t) {
-        __throw_bad_alloc();
-    }
-    virtual void do_deallocate(void *, size_t, size_t) {}
-    virtual bool do_is_equal(memory_resource const & __other) const noexcept
-    { return &__other == this; }
-};
-
-namespace {
-
-union ResourceInitHelper {
-  struct {
-    __new_delete_memory_resource_imp new_delete_res;
-    __null_memory_resource_imp       null_res;
-  } resources;
-  char dummy;
-  _LIBCPP_CONSTEXPR_SINCE_CXX14 ResourceInitHelper() : resources() {}
-  ~ResourceInitHelper() {}
-};
-
-// Pretend we're inside a system header so the compiler doesn't flag the use of the init_priority
-// attribute with a value that's reserved for the implementation (we're the implementation).
-#include "memory_resource_init_helper.h"
-
-} // end namespace
-
-
-memory_resource * new_delete_resource() noexcept {
-    return &res_init.resources.new_delete_res;
-}
-
-memory_resource * null_memory_resource() noexcept {
-    return &res_init.resources.null_res;
-}
-
-// default_memory_resource()
-
-static memory_resource *
-__default_memory_resource(bool set = false, memory_resource * new_res = nullptr) noexcept
-{
-#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
-    static constinit atomic<memory_resource*> __res{&res_init.resources.new_delete_res};
-    if (set) {
-        new_res = new_res ? new_res : new_delete_resource();
-        // TODO: Can a weaker ordering be used?
-        return _VSTD::atomic_exchange_explicit(
-            &__res, new_res, memory_order_acq_rel);
-    }
-    else {
-        return _VSTD::atomic_load_explicit(
-            &__res, memory_order_acquire);
-    }
-#elif !defined(_LIBCPP_HAS_NO_THREADS)
-    static constinit memory_resource *res = &res_init.resources.new_delete_res;
-    static mutex res_lock;
-    if (set) {
-        new_res = new_res ? new_res : new_delete_resource();
-        lock_guard<mutex> guard(res_lock);
-        memory_resource * old_res = res;
-        res = new_res;
-        return old_res;
-    } else {
-        lock_guard<mutex> guard(res_lock);
-        return res;
-    }
-#else
-    static constinit memory_resource *res = &res_init.resources.new_delete_res;
-    if (set) {
-        new_res = new_res ? new_res : new_delete_resource();
-        memory_resource * old_res = res;
-        res = new_res;
-        return old_res;
-    } else {
-        return res;
-    }
-#endif
-}
-
-memory_resource * get_default_resource() noexcept
-{
-    return __default_memory_resource();
-}
-
-memory_resource * set_default_resource(memory_resource * __new_res) noexcept
-{
-    return __default_memory_resource(true, __new_res);
-}
-
-_LIBCPP_END_NAMESPACE_LFTS_PMR
diff --git a/libcxx/src/experimental/memory_resource_init_helper.h b/libcxx/src/experimental/memory_resource_init_helper.h
deleted file mode 100644
--- a/libcxx/src/experimental/memory_resource_init_helper.h
+++ /dev/null
@@ -1,2 +0,0 @@
-#pragma GCC system_header
-static constinit ResourceInitHelper res_init _LIBCPP_INIT_PRIORITY_MAX;