diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -46,6 +46,8 @@
 
 - Implemented P0980R1 (Making ``std::string`` constexpr)
 
+- Implemented P0174R2 (Deprecating Vestigial Library Parts in C++17)
+
 - Marked the following papers as "Complete" (note that some of those might have
   been implemented in a previous release but not marked as such):
 
diff --git a/libcxx/docs/Status/Cxx17Papers.csv b/libcxx/docs/Status/Cxx17Papers.csv
--- a/libcxx/docs/Status/Cxx17Papers.csv
+++ b/libcxx/docs/Status/Cxx17Papers.csv
@@ -50,7 +50,7 @@
 "`p0088r3 <https://wg21.link/p0088r3>`__","LWG","Variant: a type-safe union for C++17","Oulu","|Complete|","4.0"
 "`p0137r1 <https://wg21.link/p0137r1>`__","CWG","Core Issue 1776: Replacement of class objects containing reference members","Oulu","|Complete|","6.0"
 "`p0163r0 <https://wg21.link/p0163r0>`__","LWG","shared_ptr::weak_type","Oulu","|Complete|","3.9"
-"`p0174r2 <https://wg21.link/p0174r2>`__","LWG","Deprecating Vestigial Library Parts in C++17","Oulu","|Partial|",""
+"`p0174r2 <https://wg21.link/p0174r2>`__","LWG","Deprecating Vestigial Library Parts in C++17","Oulu","|Complete|","15.0"
 "`p0175r1 <https://wg21.link/p0175r1>`__","LWG","Synopses for the C library","Oulu","",""
 "`p0180r2 <https://wg21.link/p0180r2>`__","LWG","Reserve a New Library Namespace for Future Standardization","Oulu","|Nothing To Do|","n/a"
 "`p0181r1 <https://wg21.link/p0181r1>`__","LWG","Ordered by Default","Oulu","*Removed in Kona*","n/a"
diff --git a/libcxx/include/__memory/allocator.h b/libcxx/include/__memory/allocator.h
--- a/libcxx/include/__memory/allocator.h
+++ b/libcxx/include/__memory/allocator.h
@@ -29,7 +29,7 @@
 
 #if _LIBCPP_STD_VER <= 17
 template <>
-class _LIBCPP_TEMPLATE_VIS allocator<void>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 allocator<void>
 {
 public:
     _LIBCPP_DEPRECATED_IN_CXX17 typedef void*             pointer;
@@ -40,7 +40,7 @@
 };
 
 template <>
-class _LIBCPP_TEMPLATE_VIS allocator<const void>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 allocator<const void>
 {
 public:
     _LIBCPP_DEPRECATED_IN_CXX17 typedef const void*       pointer;
diff --git a/libcxx/include/__memory/temporary_buffer.h b/libcxx/include/__memory/temporary_buffer.h
--- a/libcxx/include/__memory/temporary_buffer.h
+++ b/libcxx/include/__memory/temporary_buffer.h
@@ -22,7 +22,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT _LIBCPP_NO_CFI
+_LIBCPP_NODISCARD_EXT _LIBCPP_NO_CFI _LIBCPP_DEPRECATED_IN_CXX17
 pair<_Tp*, ptrdiff_t>
 get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT
 {
@@ -67,7 +67,7 @@
 }
 
 template <class _Tp>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
 void return_temporary_buffer(_Tp* __p) _NOEXCEPT
 {
   _VSTD::__libcpp_deallocate_unsized((void*)__p, _LIBCPP_ALIGNOF(_Tp));
diff --git a/libcxx/test/std/utilities/memory/default.allocator/void.depr.verify.cpp b/libcxx/test/std/utilities/memory/default.allocator/void.depr.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/utilities/memory/default.allocator/void.depr.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: c++17
+
+// Ensure allocator<void> is deprecated
+
+#include <memory>
+
+std::allocator<void> alloc; // expected-warning {{'allocator<void>' is deprecated}}
diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/depr.verify.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/depr.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/depr.verify.cpp
@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: c++17
+
+// Ensure allocator<void> is deprecated
+
+#include <memory>
+
+void test() {
+  auto a = std::get_temporary_buffer<int>(1); // expected-warning {{'get_temporary_buffer<int>' is deprecated}}
+  std::return_temporary_buffer(a.first); // expected-warning {{'return_temporary_buffer<int>' is deprecated}}
+}