diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -141,11 +141,11 @@
   or upgrade to C++11 or later. It is possible to re-enable ``std::function`` in C++03 by defining
   ``_LIBCPP_ENABLE_CXX03_FUNCTION``. This option will be removed in LLVM 16.
 
-- ``unary_function`` and ``binary_function`` are no longer available in C++17 and C++20.
-  They can be re-enabled by defining ``_LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION``.
-  They are also marked as ``[[deprecated]]`` in C++11 and later. To disable deprecation warnings
-  you have to define ``_LIBCPP_DISABLE_DEPRECATION_WARNINGS``. Note that this disables
-  all deprecation warnings.
+- ``unary_function`` and ``binary_function`` are now marked as ``[[deprecated]]`` in C++11 and later.
+  Deprecation warnings can be disabled by defining ``_LIBCPP_DISABLE_DEPRECATION_WARNINGS``, however
+  this disables all deprecation warnings, not only those for ``unary_function`` and ``binary_function``.
+  Also note that starting in LLVM 16, ``unary_function`` and ``binary_function`` will be removed entirely
+  (not only deprecated) in C++17 and above, as mandated by the Standard.
 
 - The contents of ``<codecvt>``, ``wstring_convert`` and ``wbuffer_convert`` have been marked as deprecated.
   To disable deprecation warnings you have to define ``_LIBCPP_DISABLE_DEPRECATION_WARNINGS``. Note that this
diff --git a/libcxx/include/__config b/libcxx/include/__config
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1101,6 +1101,13 @@
 #    define _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION
 #  endif // _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES
 
+// Leave the deprecation notices in by default, but don't remove unary_function and
+// binary_function entirely just yet. That way, folks will have one release to act
+// on the deprecation warnings.
+#  ifndef _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION
+#    define _LIBCPP_ENABLE_CXX17_REMOVED_UNARY_BINARY_FUNCTION
+#  endif
+
 #  if defined(_LIBCPP_ENABLE_CXX20_REMOVED_FEATURES)
 #    define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
 #    define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION
diff --git a/libcxx/test/libcxx/depr/depr.func.adaptor.typedefs/typedefs.depr_in_cxx17.verify.cpp b/libcxx/test/libcxx/depr/depr.func.adaptor.typedefs/typedefs.depr_in_cxx17.verify.cpp
--- a/libcxx/test/libcxx/depr/depr.func.adaptor.typedefs/typedefs.depr_in_cxx17.verify.cpp
+++ b/libcxx/test/libcxx/depr/depr.func.adaptor.typedefs/typedefs.depr_in_cxx17.verify.cpp
@@ -19,6 +19,12 @@
 #include <utility>
 #include "test_macros.h"
 
+// This test is disabled in LLVM 15 because we enable the removed
+// unary_function and binary_function classes by default, which means
+// that we also don't produce deprecation warnings for using their members.
+
+// expected-no-diagnostics
+#if 0
 void test_functional()
 {
     {
@@ -123,3 +129,4 @@
         (void)c;
     }
 }
+#endif