diff --git a/include/boost/unordered/detail/implementation.hpp b/include/boost/unordered/detail/implementation.hpp
index f4874d57..7bfc49dd 100644
--- a/include/boost/unordered/detail/implementation.hpp
+++ b/include/boost/unordered/detail/implementation.hpp
@@ -13,6 +13,7 @@
 #endif
 
 #include <boost/assert.hpp>
+#include <boost/core/allocator_traits.hpp>
 #include <boost/core/no_exceptions_support.hpp>
 #include <boost/core/pointer_traits.hpp>
 #include <boost/detail/select_type.hpp>
@@ -1055,441 +1056,6 @@ namespace boost {
 //
 // Allocator traits
 //
-// First our implementation, then later light wrappers around the alternatives
-
-#if BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 0
-
-#include <boost/limits.hpp>
-#include <boost/pointer_to_other.hpp>
-#include <boost/utility/enable_if.hpp>
-
-namespace boost {
-  namespace unordered {
-    namespace detail {
-
-      template <typename Alloc, typename T> struct rebind_alloc;
-
-#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
-
-      template <template <typename, typename...> class Alloc, typename U,
-        typename T, typename... Args>
-      struct rebind_alloc<Alloc<U, Args...>, T>
-      {
-        typedef Alloc<T, Args...> type;
-      };
-
-#else
-
-      template <template <typename> class Alloc, typename U, typename T>
-      struct rebind_alloc<Alloc<U>, T>
-      {
-        typedef Alloc<T> type;
-      };
-
-      template <template <typename, typename> class Alloc, typename U,
-        typename T, typename A0>
-      struct rebind_alloc<Alloc<U, A0>, T>
-      {
-        typedef Alloc<T, A0> type;
-      };
-
-      template <template <typename, typename, typename> class Alloc, typename U,
-        typename T, typename A0, typename A1>
-      struct rebind_alloc<Alloc<U, A0, A1>, T>
-      {
-        typedef Alloc<T, A0, A1> type;
-      };
-
-#endif
-
-      template <typename Alloc, typename T> struct rebind_wrap
-      {
-        template <typename X>
-        static choice1::type test(
-          choice1, typename X::BOOST_NESTED_TEMPLATE rebind<T>::other* = 0);
-        template <typename X> static choice2::type test(choice2, void* = 0);
-
-        enum
-        {
-          value = (1 == sizeof(test<Alloc>(choose())))
-        };
-
-        struct fallback
-        {
-          template <typename U> struct rebind
-          {
-            typedef typename rebind_alloc<Alloc, T>::type other;
-          };
-        };
-
-        typedef
-          typename boost::detail::if_true<value>::BOOST_NESTED_TEMPLATE then<
-            Alloc, fallback>::type::BOOST_NESTED_TEMPLATE rebind<T>::other type;
-      };
-    }
-  }
-}
-
-namespace boost {
-  namespace unordered {
-    namespace detail {
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(pointer);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(const_pointer);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(void_pointer);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(const_void_pointer);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(difference_type);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(size_type);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(
-        propagate_on_container_copy_assignment);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(
-        propagate_on_container_move_assignment);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(propagate_on_container_swap);
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(is_always_equal);
-
-#if !defined(BOOST_NO_SFINAE_EXPR)
-
-      template <typename T>
-      BOOST_UNORDERED_HAS_FUNCTION(
-        select_on_container_copy_construction, U const, (), 0);
-
-      template <typename T>
-      BOOST_UNORDERED_HAS_FUNCTION(max_size, U const, (), 0);
-
-#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
-
-      template <typename T, typename ValueType, typename... Args>
-      BOOST_UNORDERED_HAS_FUNCTION(construct, U,
-        (boost::unordered::detail::make<ValueType*>(),
-          std::declval<Args>()...),
-        2);
-
-#else
-
-      template <typename T, typename ValueType>
-      BOOST_UNORDERED_HAS_FUNCTION(construct, U,
-        (boost::unordered::detail::make<ValueType*>(),
-          boost::unordered::detail::make<ValueType const>()),
-        2);
-
-#endif
-
-      template <typename T, typename ValueType>
-      BOOST_UNORDERED_HAS_FUNCTION(
-        destroy, U, (boost::unordered::detail::make<ValueType*>()), 1);
-
-#else
-
-      template <typename T>
-      BOOST_UNORDERED_HAS_MEMBER(select_on_container_copy_construction);
-
-      template <typename T> BOOST_UNORDERED_HAS_MEMBER(max_size);
-
-      template <typename T, typename ValueType>
-      BOOST_UNORDERED_HAS_MEMBER(construct);
-
-      template <typename T, typename ValueType>
-      BOOST_UNORDERED_HAS_MEMBER(destroy);
-
-#endif
-    }
-  }
-}
-
-namespace boost {
-  namespace unordered {
-    namespace detail {
-      namespace func {
-
-        template <typename Alloc>
-        inline typename boost::enable_if<
-          boost::unordered::detail::has_select_on_container_copy_construction<
-            Alloc>,
-          Alloc>::type
-        call_select_on_container_copy_construction(const Alloc& rhs)
-        {
-          return rhs.select_on_container_copy_construction();
-        }
-
-        template <typename Alloc>
-        inline typename boost::disable_if<
-          boost::unordered::detail::has_select_on_container_copy_construction<
-            Alloc>,
-          Alloc>::type
-        call_select_on_container_copy_construction(const Alloc& rhs)
-        {
-          return rhs;
-        }
-
-        template <typename SizeType, typename Alloc>
-        inline typename boost::enable_if<
-          boost::unordered::detail::has_max_size<Alloc>, SizeType>::type
-        call_max_size(const Alloc& a)
-        {
-          return a.max_size();
-        }
-
-        template <typename SizeType, typename Alloc>
-        inline typename boost::disable_if<
-          boost::unordered::detail::has_max_size<Alloc>, SizeType>::type
-        call_max_size(const Alloc&)
-        {
-          return (std::numeric_limits<SizeType>::max)();
-        }
-      } // namespace func.
-    }
-  }
-}
-
-namespace boost {
-  namespace unordered {
-    namespace detail {
-      template <typename Alloc> struct allocator_traits
-      {
-        typedef Alloc allocator_type;
-        typedef typename Alloc::value_type value_type;
-
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(
-          Alloc, pointer, value_type*) pointer;
-
-        template <typename T>
-        struct pointer_to_other : boost::pointer_to_other<pointer, T>
-        {
-        };
-
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, const_pointer,
-          typename pointer_to_other<const value_type>::type) const_pointer;
-
-        // typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, void_pointer,
-        //    typename pointer_to_other<void>::type)
-        //    void_pointer;
-        //
-        // typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, const_void_pointer,
-        //    typename pointer_to_other<const void>::type)
-        //    const_void_pointer;
-
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(
-          Alloc, difference_type, std::ptrdiff_t) difference_type;
-
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(
-          Alloc, size_type, std::size_t) size_type;
-
-#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
-        template <typename T>
-        using rebind_alloc = typename rebind_wrap<Alloc, T>::type;
-
-        template <typename T>
-        using rebind_traits =
-          boost::unordered::detail::allocator_traits<rebind_alloc<T> >;
-#endif
-
-        static pointer allocate(Alloc& a, size_type n) { return a.allocate(n); }
-
-        // I never use this, so I'll just comment it out for now.
-        //
-        // static pointer allocate(Alloc& a, size_type n,
-        //        const_void_pointer hint)
-        //    { return DEFAULT_FUNC(allocate, pointer)(a, n, hint); }
-
-        static void deallocate(Alloc& a, pointer p, size_type n)
-        {
-          a.deallocate(p, n);
-        }
-
-      public:
-#if BOOST_UNORDERED_CXX11_CONSTRUCTION
-
-        template <typename T, typename... Args>
-        static
-          typename boost::enable_if_c<boost::unordered::detail::has_construct<
-            Alloc, T, Args...>::value>::type
-          construct(Alloc& a, T* p, BOOST_FWD_REF(Args)... x)
-        {
-          a.construct(p, boost::forward<Args>(x)...);
-        }
-
-        template <typename T, typename... Args>
-        static
-          typename boost::disable_if_c<boost::unordered::detail::has_construct<
-            Alloc, T, Args...>::value>::type
-          construct(Alloc&, T* p, BOOST_FWD_REF(Args)... x)
-        {
-          new (static_cast<void*>(p)) T(boost::forward<Args>(x)...);
-        }
-
-        template <typename T>
-        static typename boost::enable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value>::type
-        destroy(Alloc& a, T* p)
-        {
-          a.destroy(p);
-        }
-
-        template <typename T>
-        static typename boost::disable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value>::type
-        destroy(Alloc&, T* p)
-        {
-          boost::unordered::detail::func::destroy(p);
-        }
-
-#elif !defined(BOOST_NO_SFINAE_EXPR)
-
-        template <typename T>
-        static typename boost::enable_if_c<
-          boost::unordered::detail::has_construct<Alloc, T>::value>::type
-        construct(Alloc& a, T* p, T const& x)
-        {
-          a.construct(p, x);
-        }
-
-        template <typename T>
-        static typename boost::disable_if_c<
-          boost::unordered::detail::has_construct<Alloc, T>::value>::type
-        construct(Alloc&, T* p, T const& x)
-        {
-          new (static_cast<void*>(p)) T(x);
-        }
-
-        template <typename T>
-        static typename boost::enable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value>::type
-        destroy(Alloc& a, T* p)
-        {
-          a.destroy(p);
-        }
-
-        template <typename T>
-        static typename boost::disable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value>::type
-        destroy(Alloc&, T* p)
-        {
-          boost::unordered::detail::func::destroy(p);
-        }
-
-#else
-
-        // If we don't have SFINAE expressions, only call construct for the
-        // copy constructor for the allocator's value_type - as that's
-        // the only construct method that old fashioned allocators support.
-
-        template <typename T>
-        static typename boost::enable_if_c<
-          boost::unordered::detail::has_construct<Alloc, T>::value &&
-            boost::is_same<T, value_type>::value,
-          void>::type
-        construct(Alloc& a, T* p, T const& x)
-        {
-          a.construct(p, x);
-        }
-
-        template <typename T>
-        static typename boost::disable_if_c<
-          boost::unordered::detail::has_construct<Alloc, T>::value &&
-            boost::is_same<T, value_type>::value,
-          void>::type
-        construct(Alloc&, T* p, T const& x)
-        {
-          new (static_cast<void*>(p)) T(x);
-        }
-
-        template <typename T>
-        static typename boost::enable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value &&
-            boost::is_same<T, value_type>::value,
-          void>::type
-        destroy(Alloc& a, T* p)
-        {
-          a.destroy(p);
-        }
-
-        template <typename T>
-        static typename boost::disable_if_c<
-          boost::unordered::detail::has_destroy<Alloc, T>::value &&
-            boost::is_same<T, value_type>::value,
-          void>::type
-        destroy(Alloc&, T* p)
-        {
-          boost::unordered::detail::func::destroy(p);
-        }
-
-#endif
-
-        static size_type max_size(const Alloc& a)
-        {
-          return boost::unordered::detail::func::call_max_size<size_type>(a);
-        }
-
-        // Allocator propagation on construction
-
-        static Alloc select_on_container_copy_construction(Alloc const& rhs)
-        {
-          return boost::unordered::detail::func::
-            call_select_on_container_copy_construction(rhs);
-        }
-
-        // Allocator propagation on assignment and swap.
-        // Return true if lhs is modified.
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc,
-          propagate_on_container_copy_assignment,
-          false_type) propagate_on_container_copy_assignment;
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc,
-          propagate_on_container_move_assignment,
-          false_type) propagate_on_container_move_assignment;
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, propagate_on_container_swap,
-          false_type) propagate_on_container_swap;
-
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(Alloc, is_always_equal,
-          typename boost::is_empty<Alloc>::type) is_always_equal;
-      };
-    }
-  }
-}
-
-#undef BOOST_UNORDERED_DEFAULT_TYPE_TMPLT
-#undef BOOST_UNORDERED_DEFAULT_TYPE
-
-////////////////////////////////////////////////////////////////////////////////
-//
-// std::allocator_traits
-
-#elif BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 1
-
-#include <memory>
-
-namespace boost {
-  namespace unordered {
-    namespace detail {
-
-      BOOST_UNORDERED_DEFAULT_TYPE_TMPLT(is_always_equal);
-
-      template <typename Alloc>
-      struct allocator_traits : std::allocator_traits<Alloc>
-      {
-        // As is_always_equal was introduced in C++17, std::allocator_traits
-        // doesn't always have it. So use it when available, implement it
-        // ourselves when not. Would be simpler not to bother with
-        // std::allocator_traits, but I feel like I should try to use
-        // it where possible.
-        typedef BOOST_UNORDERED_DEFAULT_TYPE(std::allocator_traits<Alloc>,
-          is_always_equal,
-          BOOST_UNORDERED_DEFAULT_TYPE(Alloc, is_always_equal,
-            typename boost::is_empty<Alloc>::type)) is_always_equal;
-      };
-
-      template <typename Alloc, typename T> struct rebind_wrap
-      {
-        typedef typename std::allocator_traits<Alloc>::template rebind_alloc<T>
-          type;
-      };
-    }
-  }
-}
-
-////////////////////////////////////////////////////////////////////////////////
-//
-// boost::container::allocator_traits
-
-#elif BOOST_UNORDERED_USE_ALLOCATOR_TRAITS == 2
 
 #include <boost/container/allocator_traits.hpp>
 
@@ -1498,25 +1064,18 @@ namespace boost {
     namespace detail {
 
       template <typename Alloc>
-      struct allocator_traits : boost::container::allocator_traits<Alloc>
+      struct allocator_traits : boost::allocator_traits<Alloc>
       {
       };
 
       template <typename Alloc, typename T>
-      struct rebind_wrap : boost::container::allocator_traits<
-                             Alloc>::template portable_rebind_alloc<T>
+      struct rebind_wrap : boost::allocator_rebind<Alloc, T>
       {
       };
     }
   }
 }
 
-#else
-
-#error "Invalid BOOST_UNORDERED_USE_ALLOCATOR_TRAITS value."
-
-#endif
-
 ////////////////////////////////////////////////////////////////////////////
 // Functions used to construct nodes. Emulates variadic construction,
 // piecewise construction etc.