diff --git a/.ci_support/linux_64_.yaml b/.ci_support/linux_64_.yaml
index 1db6794..a1d9aa2 100644
--- a/.ci_support/linux_64_.yaml
+++ b/.ci_support/linux_64_.yaml
@@ -1,7 +1,3 @@
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
 bzip2:
 - '1'
 cdt_name:
diff --git a/.ci_support/linux_aarch64_.yaml b/.ci_support/linux_aarch64_.yaml
index 5616694..5c9d6b6 100644
--- a/.ci_support/linux_aarch64_.yaml
+++ b/.ci_support/linux_aarch64_.yaml
@@ -1,9 +1,5 @@
 BUILD:
 - aarch64-conda_cos7-linux-gnu
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
 bzip2:
 - '1'
 cdt_arch:
diff --git a/.ci_support/linux_ppc64le_.yaml b/.ci_support/linux_ppc64le_.yaml
index e3c3e6e..664d164 100644
--- a/.ci_support/linux_ppc64le_.yaml
+++ b/.ci_support/linux_ppc64le_.yaml
@@ -1,7 +1,3 @@
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
 bzip2:
 - '1'
 cdt_name:
diff --git a/.ci_support/osx_64_.yaml b/.ci_support/osx_64_.yaml
index b9759b6..d4c2a34 100644
--- a/.ci_support/osx_64_.yaml
+++ b/.ci_support/osx_64_.yaml
@@ -1,9 +1,5 @@
 MACOSX_DEPLOYMENT_TARGET:
-- '10.9'
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
+- '10.13'
 bzip2:
 - '1'
 channel_sources:
diff --git a/.ci_support/osx_arm64_.yaml b/.ci_support/osx_arm64_.yaml
index 342b469..9795e2e 100644
--- a/.ci_support/osx_arm64_.yaml
+++ b/.ci_support/osx_arm64_.yaml
@@ -1,9 +1,5 @@
 MACOSX_DEPLOYMENT_TARGET:
 - '11.0'
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
 bzip2:
 - '1'
 channel_sources:
diff --git a/.ci_support/win_64_.yaml b/.ci_support/win_64_.yaml
index 7fcf728..3e849f3 100644
--- a/.ci_support/win_64_.yaml
+++ b/.ci_support/win_64_.yaml
@@ -1,7 +1,3 @@
-NP_DUMMY_VER:
-- '1.21'
-PY_DUMMY_VER:
-- '3.10'
 bzip2:
 - '1'
 channel_sources:
diff --git a/.scripts/build_steps.sh b/.scripts/build_steps.sh
index 3b69f9e..4a057e4 100755
--- a/.scripts/build_steps.sh
+++ b/.scripts/build_steps.sh
@@ -34,9 +34,9 @@ CONDARC
 export CONDA_LIBMAMBA_SOLVER_NO_CHANNELS_FROM_INSTALLED=1
 
 mamba install --update-specs --yes --quiet --channel conda-forge --strict-channel-priority \
-    pip mamba conda-build boa conda-forge-ci-setup=4 "conda-build<3.28"
+    pip mamba conda-build conda-forge-ci-setup=4 "conda-build<3.28"
 mamba update --update-specs --yes --quiet --channel conda-forge --strict-channel-priority \
-    pip mamba conda-build boa conda-forge-ci-setup=4 "conda-build<3.28"
+    pip mamba conda-build conda-forge-ci-setup=4 "conda-build<3.28"
 
 # set up the condarc
 setup_conda_rc "${FEEDSTOCK_ROOT}" "${RECIPE_ROOT}" "${CONFIG_FILE}"
@@ -68,7 +68,7 @@ if [[ "${BUILD_WITH_CONDA_DEBUG:-0}" == 1 ]]; then
     # Drop into an interactive shell
     /bin/bash
 else
-    conda mambabuild "${RECIPE_ROOT}" -m "${CI_SUPPORT}/${CONFIG}.yaml" \
+    conda build "${RECIPE_ROOT}" -m "${CI_SUPPORT}/${CONFIG}.yaml" \
         --suppress-variables ${EXTRA_CB_OPTIONS:-} \
         --clobber-file "${CI_SUPPORT}/clobber_${CONFIG}.yaml" \
         --extra-meta flow_run_id="${flow_run_id:-}" remote_url="${remote_url:-}" sha="${sha:-}"
diff --git a/.scripts/run_osx_build.sh b/.scripts/run_osx_build.sh
index c2f2f2c..01557f7 100755
--- a/.scripts/run_osx_build.sh
+++ b/.scripts/run_osx_build.sh
@@ -26,9 +26,9 @@ export CONDA_SOLVER="libmamba"
 export CONDA_LIBMAMBA_SOLVER_NO_CHANNELS_FROM_INSTALLED=1
 
 mamba install --update-specs --quiet --yes --channel conda-forge --strict-channel-priority \
-    pip mamba conda-build boa conda-forge-ci-setup=4 "conda-build<3.28"
+    pip mamba conda-build conda-forge-ci-setup=4 "conda-build<3.28"
 mamba update --update-specs --yes --quiet --channel conda-forge --strict-channel-priority \
-    pip mamba conda-build boa conda-forge-ci-setup=4 "conda-build<3.28"
+    pip mamba conda-build conda-forge-ci-setup=4 "conda-build<3.28"
 
 
 
@@ -81,7 +81,7 @@ else
         EXTRA_CB_OPTIONS="${EXTRA_CB_OPTIONS:-} --no-test"
     fi
 
-    conda mambabuild ./recipe -m ./.ci_support/${CONFIG}.yaml \
+    conda build ./recipe -m ./.ci_support/${CONFIG}.yaml \
         --suppress-variables ${EXTRA_CB_OPTIONS:-} \
         --clobber-file ./.ci_support/clobber_${CONFIG}.yaml \
         --extra-meta flow_run_id="$flow_run_id" remote_url="$remote_url" sha="$sha"
diff --git a/.scripts/run_win_build.bat b/.scripts/run_win_build.bat
index c186760..94596cc 100755
--- a/.scripts/run_win_build.bat
+++ b/.scripts/run_win_build.bat
@@ -24,7 +24,7 @@ set "CONDA_LIBMAMBA_SOLVER_NO_CHANNELS_FROM_INSTALLED=1"
 
 :: Provision the necessary dependencies to build the recipe later
 echo Installing dependencies
-mamba.exe install "python=3.10" pip mamba conda-build boa conda-forge-ci-setup=4 "conda-build<3.28" -c conda-forge --strict-channel-priority --yes
+mamba.exe install "python=3.10" pip mamba conda-build conda-forge-ci-setup=4 "conda-build<3.28" -c conda-forge --strict-channel-priority --yes
 if !errorlevel! neq 0 exit /b !errorlevel!
 
 :: Set basic configuration
@@ -55,7 +55,7 @@ call :end_group
 
 :: Build the recipe
 echo Building recipe
-conda.exe mambabuild "recipe" -m .ci_support\%CONFIG%.yaml --suppress-variables %EXTRA_CB_OPTIONS%
+conda.exe build "recipe" -m .ci_support\%CONFIG%.yaml --suppress-variables %EXTRA_CB_OPTIONS%
 if !errorlevel! neq 0 exit /b !errorlevel!
 
 :: Prepare some environment variables for the upload step
diff --git a/build-locally.py b/build-locally.py
index 3f4b7a7..e0d408d 100755
--- a/build-locally.py
+++ b/build-locally.py
@@ -64,8 +64,9 @@ def verify_config(ns):
     elif ns.config.startswith("osx"):
         if "OSX_SDK_DIR" not in os.environ:
             raise RuntimeError(
-                "Need OSX_SDK_DIR env variable set. Run 'export OSX_SDK_DIR=SDKs' "
-                "to download the SDK automatically to 'SDKs/MacOSX<ver>.sdk'. "
+                "Need OSX_SDK_DIR env variable set. Run 'export OSX_SDK_DIR=$PWD/SDKs' "
+                "to download the SDK automatically to '$PWD/SDKs/MacOSX<ver>.sdk'. "
+                "Note: OSX_SDK_DIR must be set to an absolute path. "
                 "Setting this variable implies agreement to the licensing terms of the SDK by Apple."
             )
 
diff --git a/recipe/bld.bat b/recipe/bld.bat
index 5b4c255..e61dbb0 100755
--- a/recipe/bld.bat
+++ b/recipe/bld.bat
@@ -23,6 +23,7 @@ mkdir temp_prefix
     variant=release ^
     threading=multi ^
     link=shared ^
+    cxxstd=20 ^
     -s NO_COMPRESSION=0 ^
     -s NO_ZLIB=0 ^
     -s NO_BZIP2=0 ^
diff --git a/recipe/build.sh b/recipe/build.sh
index 26c5b74..94b2535 100755
--- a/recipe/build.sh
+++ b/recipe/build.sh
@@ -17,6 +17,8 @@ CXXFLAGS="${CXXFLAGS} -fPIC"
 
 if [[ "${target_platform}" == osx* ]]; then
     TOOLSET=clang
+    # see https://conda-forge.org/docs/maintainer/knowledge_base/#newer-c-features-with-old-sdk
+    CXXFLAGS="${CXXFLAGS} -D_LIBCPP_DISABLE_AVAILABILITY"
 elif [[ "${target_platform}" == linux* ]]; then
     TOOLSET=gcc
 fi
@@ -75,6 +77,7 @@ mkdir temp_prefix
     include="${INCLUDE_PATH}" \
     cxxflags="${CXXFLAGS}" \
     linkflags="${LINKFLAGS}" \
+    cxxstd=20 \
     --layout=system \
     -j"${CPU_COUNT}" \
     install
diff --git a/recipe/conda_build_config.yaml b/recipe/conda_build_config.yaml
index 3518139..0654d29 100644
--- a/recipe/conda_build_config.yaml
+++ b/recipe/conda_build_config.yaml
@@ -1,6 +1,3 @@
-# we only need _a_ python version to build the headers for libboost-headers,
-# putting it in CBC means it's accessible also in the build scripts
-PY_DUMMY_VER:
-  - "3.10"
-NP_DUMMY_VER:
-  - "1.21"
+# Bump MacOs target to 10.13 for Boost.Cobalt / C++20 support
+MACOSX_DEPLOYMENT_TARGET:
+  - '10.13' # [osx and x86_64]
diff --git a/recipe/meta.yaml b/recipe/meta.yaml
index ddfd99e..5ae9170 100644
--- a/recipe/meta.yaml
+++ b/recipe/meta.yaml
@@ -1,7 +1,7 @@
 {% set version = "1.84.0" %}
 
 {% set boost_libs = [
-    "atomic", "chrono", "container", "context", "contract", "coroutine",
+    "atomic", "chrono", "cobalt", "container", "context", "contract", "coroutine",
     "date_time", "filesystem", "graph", "iostreams", "locale", "log", "log_setup",
     "math_c99", "math_c99f", "math_tr1", "math_tr1f", "prg_exec_monitor",
     "program_options", "random", "regex", "serialization", "system", "thread",
@@ -11,6 +11,11 @@
 {% set boost_libs_static_only = ["exception", "test_exec_monitor"] %}
 {% set boost_libs_py = ["python%s" % py, "numpy%s" % py] %}
 
+# we only need _a_ python version to build the headers for libboost-headers,
+# make it accessible in the build scripts via build/script_env below.
+{% set PY_DUMMY_VER = "3.10" %}
+{% set NP_DUMMY_VER = "1.21" %}
+
 package:
   name: boost-split
   version: {{ version }}
@@ -21,16 +26,20 @@ source:
   patches:
     # ensure our compiler flags get used during bootstrapping 
     - patches/0001-Add-default-value-for-cxx-and-cxxflags-options-for-t.patch
+    - patches/0002-Reimplement-string_set-as-any_string.patch
 
 build:
-  number: 1
+  number: 2
+  script_env:
+    - PY_DUMMY_VER={{ PY_DUMMY_VER }}
+    - NP_DUMMY_VER={{ NP_DUMMY_VER }}
 
 requirements:
   build:
     - {{ compiler('cxx') }}
     - cross-python_{{ target_platform }}     # [build_platform != target_platform]
-    - python {{ PY_DUMMY_VER }} *cpython     # [build_platform != target_platform]
-    - numpy {{ NP_DUMMY_VER }}               # [build_platform != target_platform]
+    - python {{ PY_DUMMY_VER }}.* *_cpython  # [build_platform != target_platform]
+    - numpy {{ NP_DUMMY_VER }}.*             # [build_platform != target_platform]
   host:
     - icu               # [unix]
     - xz                # [unix]
@@ -38,8 +47,8 @@ requirements:
     - zlib
     - zstd
     # see conda_build_config
-    - python {{ PY_DUMMY_VER }} *cpython
-    - numpy {{ NP_DUMMY_VER }}
+    - python {{ PY_DUMMY_VER }}.* *_cpython
+    - numpy {{ NP_DUMMY_VER }}.*
 
 outputs:
   - name: libboost-headers
@@ -97,6 +106,8 @@ outputs:
         - xz
         - zlib
         - zstd
+      run:
+        - __osx >={{ MACOSX_DEPLOYMENT_TARGET|default("10.9") }}  # [osx and x86_64]
       run_constrained:
         # Anaconda's output is also called libboost; therefore we automatically
         # avoid issues of co-installability, because a package with the same name
diff --git a/recipe/patches/0002-Reimplement-string_set-as-any_string.patch b/recipe/patches/0002-Reimplement-string_set-as-any_string.patch
new file mode 100644
index 0000000..43a0be3
--- /dev/null
+++ b/recipe/patches/0002-Reimplement-string_set-as-any_string.patch
@@ -0,0 +1,335 @@
+From c5e8f02c903696a213fc4b710f6740ccd1f07f4e Mon Sep 17 00:00:00 2001
+From: Alexander Grund <Flamefire@users.noreply.github.com>
+Date: Sun, 3 Dec 2023 20:06:27 +0100
+Subject: [PATCH] Reimplement `string_set` as `any_string`
+
+Use a better name for a type-erased string implemented using
+`dynamic_cast` instead of storing&comparing the `typeid` of the char
+type used.
+This is a workaround for missing typeinfo for `char8_t` on e.g. libc++
+on FreeBSD 13.1.
+It also simplifies memory management size calc/copy implementation.
+---
+ boost/locale/detail/any_string.hpp | 71 ++++++++++++++++++++++
+ boost/locale/formatting.hpp        | 51 ++--------------
+ libs/locale/src/boost/locale/shared/formatting.cpp     | 45 --------------
+ libs/locale/test/test_ios_info.cpp        | 64 +++++++++++++++----
+ 4 files changed, 127 insertions(+), 104 deletions(-)
+ create mode 100644 boost/locale/detail/any_string.hpp
+
+diff --git a/boost/locale/detail/any_string.hpp b/boost/locale/detail/any_string.hpp
+new file mode 100644
+index 00000000..c0cc7ffb
+--- /dev/null
++++ b/boost/locale/detail/any_string.hpp
+@@ -0,0 +1,71 @@
++//
++// Copyright (c) 2023 Alexander Grund
++//
++// Distributed under the Boost Software License, Version 1.0.
++// https://www.boost.org/LICENSE_1_0.txt
++
++#ifndef BOOST_LOCALE_DETAIL_ANY_STRING_HPP_INCLUDED
++#define BOOST_LOCALE_DETAIL_ANY_STRING_HPP_INCLUDED
++
++#include <boost/locale/config.hpp>
++#include <boost/assert.hpp>
++#include <boost/utility/string_view.hpp>
++#include <memory>
++#include <stdexcept>
++#include <string>
++
++/// \cond INTERNAL
++namespace boost { namespace locale { namespace detail {
++    /// Type-erased std::basic_string
++    class any_string {
++        struct BOOST_SYMBOL_VISIBLE base {
++            virtual ~base() = default;
++            virtual base* clone() const = 0;
++
++        protected:
++            base() = default;
++            base(const base&) = default;
++            base(base&&) = delete;
++            base& operator=(const base&) = default;
++            base& operator=(base&&) = delete;
++        };
++        template<typename Char>
++        struct BOOST_SYMBOL_VISIBLE impl : base {
++            explicit impl(const boost::basic_string_view<Char> value) : s(value) {}
++            impl* clone() const override { return new impl(*this); }
++            std::basic_string<Char> s;
++        };
++
++        std::unique_ptr<const base> s_;
++
++    public:
++        any_string() = default;
++        any_string(const any_string& other) : s_(other.s_ ? other.s_->clone() : nullptr) {}
++        any_string(any_string&&) = default;
++        any_string& operator=(any_string other) // Covers the copy and move assignment
++        {
++            s_.swap(other.s_);
++            return *this;
++        }
++
++        template<typename Char>
++        void set(const boost::basic_string_view<Char> s)
++        {
++            BOOST_ASSERT(!s.empty());
++            s_.reset(new impl<Char>(s));
++        }
++
++        template<typename Char>
++        std::basic_string<Char> get() const
++        {
++            if(!s_)
++                throw std::bad_cast();
++            return dynamic_cast<const impl<Char>&>(*s_).s;
++        }
++    };
++
++}}} // namespace boost::locale::detail
++
++/// \endcond
++
++#endif
+diff --git a/boost/locale/formatting.hpp b/boost/locale/formatting.hpp
+index d14e6f69..e3c8619e 100644
+--- a/boost/locale/formatting.hpp
++++ b/boost/locale/formatting.hpp
+@@ -8,15 +8,13 @@
+ #ifndef BOOST_LOCALE_FORMATTING_HPP_INCLUDED
+ #define BOOST_LOCALE_FORMATTING_HPP_INCLUDED
+ 
++#include <boost/locale/detail/any_string.hpp>
+ #include <boost/locale/time_zone.hpp>
+-#include <boost/assert.hpp>
+-#include <boost/utility/string_view.hpp>
+ #include <cstdint>
+ #include <cstring>
+ #include <istream>
+ #include <ostream>
+ #include <string>
+-#include <typeinfo>
+ 
+ #ifdef BOOST_MSVC
+ #    pragma warning(push)
+@@ -130,13 +128,13 @@ namespace boost { namespace locale {
+         template<typename CharType>
+         void date_time_pattern(const std::basic_string<CharType>& str)
+         {
+-            date_time_pattern_set().set<CharType>(str);
++            datetime_.set<CharType>(str);
+         }
+         /// Get date/time pattern (strftime like)
+         template<typename CharType>
+         std::basic_string<CharType> date_time_pattern() const
+         {
+-            return date_time_pattern_set().get<CharType>();
++            return datetime_.get<CharType>();
+         }
+ 
+         /// \cond INTERNAL
+@@ -144,51 +142,10 @@ namespace boost { namespace locale {
+         /// \endcond
+ 
+     private:
+-        class string_set;
+-
+-        const string_set& date_time_pattern_set() const;
+-        string_set& date_time_pattern_set();
+-
+-        class BOOST_LOCALE_DECL string_set {
+-        public:
+-            string_set();
+-            ~string_set();
+-            string_set(const string_set& other);
+-            string_set& operator=(string_set other);
+-            void swap(string_set& other);
+-
+-            template<typename Char>
+-            void set(const boost::basic_string_view<Char> s)
+-            {
+-                BOOST_ASSERT(!s.empty());
+-                delete[] ptr;
+-                ptr = nullptr;
+-                type = &typeid(Char);
+-                size = sizeof(Char) * s.size();
+-                ptr = size ? new char[size] : nullptr;
+-                memcpy(ptr, s.data(), size);
+-            }
+-
+-            template<typename Char>
+-            std::basic_string<Char> get() const
+-            {
+-                if(type == nullptr || *type != typeid(Char))
+-                    throw std::bad_cast();
+-                std::basic_string<Char> result(size / sizeof(Char), Char(0));
+-                memcpy(&result.front(), ptr, size);
+-                return result;
+-            }
+-
+-        private:
+-            const std::type_info* type;
+-            size_t size;
+-            char* ptr;
+-        };
+-
+         uint64_t flags_;
+         int domain_id_;
+         std::string time_zone_;
+-        string_set datetime_;
++        detail::any_string datetime_;
+     };
+ 
+     /// \brief This namespace includes all manipulators that can be used on IO streams
+diff --git a/libs/locale/src/boost/locale/shared/formatting.cpp b/libs/locale/src/boost/locale/shared/formatting.cpp
+index 489d1fd5..457ba782 100644
+--- a/libs/locale/src/boost/locale/shared/formatting.cpp
++++ b/libs/locale/src/boost/locale/shared/formatting.cpp
+@@ -7,43 +7,8 @@
+ #include <boost/locale/date_time.hpp>
+ #include <boost/locale/formatting.hpp>
+ #include "boost/locale/shared/ios_prop.hpp"
+-#include <algorithm>
+-#include <typeinfo>
+ 
+ namespace boost { namespace locale {
+-
+-    ios_info::string_set::string_set() : type(nullptr), size(0), ptr(nullptr) {}
+-    ios_info::string_set::~string_set()
+-    {
+-        delete[] ptr;
+-    }
+-    ios_info::string_set::string_set(const string_set& other)
+-    {
+-        if(other.ptr != nullptr) {
+-            ptr = new char[other.size];
+-            size = other.size;
+-            type = other.type;
+-            memcpy(ptr, other.ptr, size);
+-        } else {
+-            ptr = nullptr;
+-            size = 0;
+-            type = nullptr;
+-        }
+-    }
+-
+-    void ios_info::string_set::swap(string_set& other)
+-    {
+-        std::swap(type, other.type);
+-        std::swap(size, other.size);
+-        std::swap(ptr, other.ptr);
+-    }
+-
+-    ios_info::string_set& ios_info::string_set::operator=(string_set other)
+-    {
+-        swap(other);
+-        return *this;
+-    }
+-
+     ios_info::ios_info() : flags_(0), domain_id_(0), time_zone_(time_zone::global()) {}
+ 
+     ios_info::~ios_info() = default;
+@@ -105,16 +70,6 @@ namespace boost { namespace locale {
+         return time_zone_;
+     }
+ 
+-    const ios_info::string_set& ios_info::date_time_pattern_set() const
+-    {
+-        return datetime_;
+-    }
+-
+-    ios_info::string_set& ios_info::date_time_pattern_set()
+-    {
+-        return datetime_;
+-    }
+-
+     ios_info& ios_info::get(std::ios_base& ios)
+     {
+         return impl::ios_prop<ios_info>::get(ios);
+diff --git a/libs/locale/test/test_ios_info.cpp b/libs/locale/test/test_ios_info.cpp
+index 9b63aaed..79179a8f 100644
+--- a/libs/locale/test/test_ios_info.cpp
++++ b/libs/locale/test/test_ios_info.cpp
+@@ -105,18 +105,6 @@ void test_member_methods()
+ 
+         info.date_time_pattern(std::string("Pattern"));
+         TEST_EQ(info.date_time_pattern<char>(), "Pattern");
+-
+-        info.date_time_pattern(ascii_to<wchar_t>("WChar Pattern"));
+-        TEST_EQ(info.date_time_pattern<wchar_t>(), ascii_to<wchar_t>("WChar Pattern"));
+-        TEST_THROWS(info.date_time_pattern<char>(), std::bad_cast);
+-
+-        info.date_time_pattern(ascii_to<char16_t>("Char16 Pattern"));
+-        TEST_THROWS(info.date_time_pattern<wchar_t>(), std::bad_cast);
+-        TEST_EQ(info.date_time_pattern<char16_t>(), ascii_to<char16_t>("Char16 Pattern"));
+-
+-        info.date_time_pattern(ascii_to<char32_t>("Char32 Pattern"));
+-        TEST_THROWS(info.date_time_pattern<char16_t>(), std::bad_cast);
+-        TEST_EQ(info.date_time_pattern<char32_t>(), ascii_to<char32_t>("Char32 Pattern"));
+     }
+ }
+ 
+@@ -212,8 +200,60 @@ void test_manipulators()
+     TEST_EQ(info2.date_time_pattern<wchar_t>(), L"My TZ");
+ }
+ 
++void test_any_string()
++{
++    boost::locale::detail::any_string s;
++    TEST_THROWS(s.get<char>(), std::bad_cast);
++    TEST_THROWS(s.get<wchar_t>(), std::bad_cast);
++
++    s.set<char>("Char Pattern");
++    TEST_EQ(s.get<char>(), "Char Pattern");
++    TEST_THROWS(s.get<wchar_t>(), std::bad_cast);
++
++    s.set<wchar_t>(ascii_to<wchar_t>("WChar Pattern"));
++    TEST_EQ(s.get<wchar_t>(), ascii_to<wchar_t>("WChar Pattern"));
++    TEST_THROWS(s.get<char>(), std::bad_cast);
++
++    s.set<char16_t>(ascii_to<char16_t>("Char16 Pattern"));
++    TEST_EQ(s.get<char16_t>(), ascii_to<char16_t>("Char16 Pattern"));
++    TEST_THROWS(s.get<char>(), std::bad_cast);
++
++    s.set<char32_t>(ascii_to<char32_t>("Char32 Pattern"));
++    TEST_EQ(s.get<char32_t>(), ascii_to<char32_t>("Char32 Pattern"));
++    TEST_THROWS(s.get<char16_t>(), std::bad_cast);
++
++#ifndef BOOST_LOCALE_NO_CXX20_STRING8
++    s.set<char8_t>(ascii_to<char8_t>("Char8 Pattern"));
++    TEST_EQ(s.get<char8_t>(), ascii_to<char8_t>("Char8 Pattern"));
++    TEST_THROWS(s.get<char32_t>(), std::bad_cast);
++#endif
++
++    boost::locale::detail::any_string s1, s2, empty;
++    s1.set<char>("Char");
++    s2.set<wchar_t>(ascii_to<wchar_t>("WChar"));
++    // Copy ctor
++    boost::locale::detail::any_string s3(s1);
++    TEST_EQ(s3.get<char>(), "Char");
++    TEST_EQ(s1.get<char>(), "Char");
++    // Ensure deep copy
++    s3.set<char>("Foo");
++    TEST_EQ(s3.get<char>(), "Foo");
++    TEST_EQ(s1.get<char>(), "Char");
++    // Copy assign
++    s3 = s2;
++    TEST_EQ(s3.get<wchar_t>(), ascii_to<wchar_t>("WChar"));
++    TEST_EQ(s2.get<wchar_t>(), ascii_to<wchar_t>("WChar"));
++    // Move assign
++    s3 = std::move(s1);
++    TEST_EQ(s3.get<char>(), "Char");
++    // From empty
++    s3 = empty;
++    TEST_THROWS(s3.get<char>(), std::bad_cast);
++}
++
+ void test_main(int /*argc*/, char** /*argv*/)
+ {
++    test_any_string();
+     test_member_methods();
+     test_manipulators();
+ }