diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -210,12 +210,12 @@
 option(LIBCXX_EXTRA_SITE_DEFINES "Extra defines to add into __config_site")
 option(LIBCXX_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
 
-cmake_dependent_option(LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS
+option(LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS
   "Whether to include the old Debug mode symbols in the compiled library. This
    is provided for backwards compatibility since the compiled library used to
    always contain those symbols, regardless of whether the library was built
-   with the debug mode enabled." ON
-   "LIBCXX_ABI_VERSION EQUAL 1" OFF) # Always OFF in ABI version != 1
+   with the debug mode enabled. This is OFF by default, please contact the libc++
+   developers if you need to turn this on, as this will be removed in the future." OFF)
 
 # ABI Library options ---------------------------------------------------------
 if (LIBCXX_TARGETING_MSVC)
diff --git a/libcxx/cmake/caches/Apple.cmake b/libcxx/cmake/caches/Apple.cmake
--- a/libcxx/cmake/caches/Apple.cmake
+++ b/libcxx/cmake/caches/Apple.cmake
@@ -9,7 +9,6 @@
 set(LIBCXX_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
 set(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT ON CACHE BOOL "")
-set(LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS OFF CACHE BOOL "")
 set(LIBCXX_ENABLE_VENDOR_AVAILABILITY_ANNOTATIONS ON CACHE BOOL "")
 set(LIBCXX_ENABLE_INCOMPLETE_FEATURES OFF CACHE BOOL "")
 
diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -144,6 +144,12 @@
   as a return type instead of relying on the type of ``valarray``-expressions, which is
   not guaranteed by the Standard anyway.
 
+- By default, the legacy debug mode symbols are not provided with the library anymore. If
+  you are a vendor and need to re-enable them, please use the ``LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS``
+  CMake flag instead, and contact the libc++ developers as this will be removed in
+  the future. Furthermore, please note that ``LIBCXX_ENABLE_DEBUG_MODE_SUPPORT`` is
+  not honored anymore.
+
 Build System Changes
 --------------------
 
@@ -175,7 +181,3 @@
   configuration and isn't supported by one of the configurations in ``libcxx/test/configs``,
   ``libcxxabi/test/configs`` or ``libunwind/test/configs``, please move to one of those
   configurations or define your own.
-
-- The ``LIBCXX_ENABLE_DEBUG_MODE_SUPPORT`` CMake configuration is not supported anymore. If you
-  were disabling support for the debug mode with that flag, please use ``LIBCXX_ENABLE_BACKWARDS_COMPATIBILITY_DEBUG_MODE_SYMBOLS=OFF``
-  instead.