DOCSP-45307: Drop external polyfill library support

source/api-abi-versioning.txt

@@ -193,8 +193,6 @@ Examples of expected library filenames (with a brief description of notable feat
 - ``bsoncxx-v_noabi-dhs-x64-v142-mdd.dll`` (debug build configuration)
 - ``bsoncxx-v_noabi-rts-x64-v142-md.dll`` (link with mongoc static libraries)
 - ``bsoncxx-v_noabi-rhi-x64-v142-md.dll`` (bsoncxx as polyfill library)
-- ``bsoncxx-v_noabi-rhm-x64-v142-md.dll`` (mnmlstc/core as polyfill library)
-- ``bsoncxx-v_noabi-rhb-x64-v142-md.dll`` (Boost as polyfill library)
 - ``bsoncxx-v1-rhs-x64-v142-md.dll``      (ABI version number 1)
 - ``bsoncxx-v2-rhs-x64-v142-md.dll``      (ABI version number 2)
 

source/get-started/download-and-install.txt

@@ -24,12 +24,13 @@ Download and Install
       - `CMake <https://cmake.org/>`__ v3.15 or later
       - `pkg-config <https://www.freedesktop.org/wiki/Software/pkg-config/>`__
 
-      .. note:: C++17 Polyfills
+      .. note:: Pre-C++17 Configurations
 
          This tutorial configures the {+driver-short+} to use the C++17 standard
          library. If you want to install the driver for pre-C++17 configurations,
-         you must choose a C++17 polyfill library. To learn more about C++17
-         polyfills, see the :ref:`cpp-polyfill-selection` guide.
+         set the ``CMAKE_CXX_STANDARD`` configuration option to your C++ version.
+         By default, the driver enables the bsoncxx polyfill library for pre-C++17
+         configurations.
 
    .. step:: Download the {+driver-short+}
 

source/index.txt

@@ -19,7 +19,6 @@ MongoDB C++ Driver
    Run a Command </run-command>
    Security </security>
    Specialized Data Formats </data-formats>
-   C++17 Polyfill </polyfill-selection>
    Advanced Configuration & Installation </advanced-installation>
    Thread & Fork Safety </thread-safety>
    API & ABI Versioning </api-abi-versioning>
@@ -83,12 +82,6 @@ Specialized Data Formats
 Learn how to work with specialized data formats and custom types in the
 :ref:`cpp-data-formats` section.
 
-Choose a C++17 Polyfill
------------------------
-
-Learn how to a choose a polyfill library implementation for
-pre-C++ 17 configurations in the :ref:`cpp-polyfill-selection` section.
-
 Advanced Installation Options
 -----------------------------
 

source/whats-new.txt

@@ -22,6 +22,7 @@ Overview
 
 Learn what's new in:
 
+* :ref:`Version 4.0 <version-4.0>`
 * :ref:`Version 3.11 <version-3.11>`
 * :ref:`Version 3.10 <version-3.10>`
 * :ref:`Version 3.9 <version-3.9>`
@@ -73,6 +74,22 @@ New versions of the {+driver-short+} can introduce the following types of breaki
      - Drops support for platform A, compiler B, or architecture C.
 
 .. _upcoming-breaking-changes:
+.. _version-4.0:
+
+What's New in 4.0
+-----------------
+
+.. warning:: Breaking Changes
+
+   The v4.0 driver introduces the following breaking changes:
+
+   - Drops support for the Boost and MNMLSTC/core external polyfill libraries. You can no
+     longer set the following configuration options:
+
+     - ``ENABLE_BSONCXX_POLY_USE_IMPLS``. This option is implicitly set to ``ON``.
+     - ``BSONCXX_POLY_USE_MNMLSTC``.
+     - ``BSONCXX_POLY_USE_SYSTEM_MNMLSTC``.
+     - ``BSONCXX_POLY_USE_BOOST``.
 
 .. _version-3.11: