diff --git a/.travis.yml b/.travis.yml
index fc68de4..b4b3e0f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,5 @@
 # Copyright 2016, 2017, 2018 Peter Dimov
+# Copyright 2019 Andrey Semashev
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
 
@@ -22,12 +23,10 @@ matrix:
     - env: BOGUS_JOB=true
 
   include:
+# gcc, Linux
     - os: linux
-      compiler: g++
-      env: TOOLSET=gcc COMPILER=g++ CXXSTD=03,11
-
-    - os: linux
-      compiler: g++-4.4
+      dist: trusty
+      compiler: gcc-4.4
       env: TOOLSET=gcc COMPILER=g++-4.4 CXXSTD=98,0x
       addons:
         apt:
@@ -37,7 +36,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-4.6
+      dist: trusty
+      compiler: gcc-4.6
       env: TOOLSET=gcc COMPILER=g++-4.6 CXXSTD=03,0x
       addons:
         apt:
@@ -47,7 +47,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-4.7
+      dist: trusty
+      compiler: gcc-4.7
       env: TOOLSET=gcc COMPILER=g++-4.7 CXXSTD=03,11
       addons:
         apt:
@@ -57,7 +58,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-4.8
+      dist: xenial
+      compiler: gcc-4.8
       env: TOOLSET=gcc COMPILER=g++-4.8 CXXSTD=03,11
       addons:
         apt:
@@ -65,8 +67,10 @@ matrix:
             - g++-4.8
           sources:
             - ubuntu-toolchain-r-test
+
     - os: linux
-      compiler: g++-4.9
+      dist: xenial
+      compiler: gcc-4.9
       env: TOOLSET=gcc COMPILER=g++-4.9 CXXSTD=03,11
       addons:
         apt:
@@ -76,7 +80,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-5
+      dist: xenial
+      compiler: gcc-5
       env: TOOLSET=gcc COMPILER=g++-5 CXXSTD=03,11,14,1z
       addons:
         apt:
@@ -86,7 +91,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-6
+      dist: xenial
+      compiler: gcc-6
       env: TOOLSET=gcc COMPILER=g++-6 CXXSTD=03,11,14,1z
       addons:
         apt:
@@ -96,7 +102,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-7
+      dist: xenial
+      compiler: gcc-7
       env: TOOLSET=gcc COMPILER=g++-7 CXXSTD=03,11,14,17
       addons:
         apt:
@@ -106,7 +113,8 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: g++-8
+      dist: xenial
+      compiler: gcc-8
       env: TOOLSET=gcc COMPILER=g++-8 CXXSTD=03,11,14,17
       addons:
         apt:
@@ -116,27 +124,45 @@ matrix:
             - ubuntu-toolchain-r-test
 
     - os: linux
-      compiler: clang++
-      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11
-
-    - os: linux
-      compiler: /usr/bin/clang++
-      env: TOOLSET=clang COMPILER=/usr/bin/clang++ CXXSTD=03,11
+      dist: bionic
+      compiler: gcc-9
+      env: TOOLSET=gcc COMPILER=g++-9 CXXSTD=03,11,14,17
       addons:
         apt:
           packages:
-            - clang-3.3
+            - g++-9
+          sources:
+            - sourceline: "ppa:ubuntu-toolchain-r/test"
 
     - os: linux
-      compiler: /usr/bin/clang++
-      env: TOOLSET=clang COMPILER=/usr/bin/clang++ CXXSTD=03,11
+      dist: bionic
+      compiler: gcc-10
+      env: TOOLSET=gcc COMPILER=g++-10 CXXSTD=03,11,14,17,20
+      addons:
+        apt:
+          packages:
+            - g++-10
+          sources:
+            - sourceline: "ppa:ubuntu-toolchain-r/test"
+
+# clang, Linux
+    - os: linux
+      dist: trusty
+      compiler: clang-3.4
+      env: TOOLSET=clang COMPILER=clang++-3.4 CXXSTD=03,11
       addons:
         apt:
           packages:
             - clang-3.4
+            - libstdc++-4.9-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.4 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-3.5
+      dist: trusty
+      compiler: clang-3.5
       env: TOOLSET=clang COMPILER=clang++-3.5 CXXSTD=03,11,14,1z
       addons:
         apt:
@@ -145,109 +171,191 @@ matrix:
             - libstdc++-4.9-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.5
+            - sourceline: "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.5 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-3.6
+      dist: trusty
+      compiler: clang-3.6
       env: TOOLSET=clang COMPILER=clang++-3.6 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-3.6
+            - libstdc++-5-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.6
+            - sourceline: "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.6 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-3.7
+      dist: trusty
+      compiler: clang-3.7
       env: TOOLSET=clang COMPILER=clang++-3.7 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-3.7
+            - libstdc++-5-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.7
+            - sourceline: "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.7 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-3.8
+      dist: xenial
+      compiler: clang-3.8
       env: TOOLSET=clang COMPILER=clang++-3.8 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-3.8
-            - libstdc++-4.9-dev
+            - libstdc++-6-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.8
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.8 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-3.9
+      dist: xenial
+      compiler: clang-3.9
       env: TOOLSET=clang COMPILER=clang++-3.9 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-3.9
-            - libstdc++-4.9-dev
+            - libstdc++-6-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.9
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.9 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-4.0
+      dist: xenial
+      compiler: clang-4
       env: TOOLSET=clang COMPILER=clang++-4.0 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-4.0
+            - libstdc++-6-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-4.0
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-4.0 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-5.0
+      dist: xenial
+      compiler: clang-5
       env: TOOLSET=clang COMPILER=clang++-5.0 CXXSTD=03,11,14,1z
       addons:
         apt:
           packages:
             - clang-5.0
+            - libstdc++-7-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-5.0
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-6.0
-      env: TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=03,11,14,1z
+      dist: xenial
+      compiler: clang-6
+      env: TOOLSET=clang COMPILER=clang++-6.0 CXXSTD=03,11,14,17
       addons:
         apt:
           packages:
             - clang-6.0
+            - libstdc++-8-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-6.0
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-6.0 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-7
+      dist: xenial
+      compiler: clang-7
       env: TOOLSET=clang COMPILER=clang++-7 CXXSTD=03,11,14,17
       addons:
         apt:
           packages:
             - clang-7
+            - libstdc++-8-dev
           sources:
             - ubuntu-toolchain-r-test
-            - llvm-toolchain-trusty-7
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-7 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
     - os: linux
-      compiler: clang++-libc++
-      env: TOOLSET=clang COMPILER=clang++-libc++ CXXSTD=03,11,14,1z
+      dist: xenial
+      compiler: clang-8
+      env: TOOLSET=clang COMPILER=clang++-8 CXXSTD=03,11,14,17
       addons:
         apt:
           packages:
-            - libc++-dev
+            - clang-8
+            - libstdc++-8-dev
+          sources:
+            - ubuntu-toolchain-r-test
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-8 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
 
-    - os: osx
-      compiler: clang++
-      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+    - os: linux
+      dist: xenial
+      compiler: clang-9
+      env: TOOLSET=clang COMPILER=clang++-9 CXXSTD=03,11,14,17
+      addons:
+        apt:
+          packages:
+            - clang-9
+            - libstdc++-9-dev
+          sources:
+            - sourceline: "ppa:ubuntu-toolchain-r/test"
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-9 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
+
+    - os: linux
+      dist: xenial
+      compiler: clang-10
+      env: TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,20
+      addons:
+        apt:
+          packages:
+            - clang-10
+            - libstdc++-9-dev
+          sources:
+            - sourceline: "ppa:ubuntu-toolchain-r/test"
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
+
+    - os: linux
+      dist: xenial
+      compiler: clang-libc++
+      env: TOOLSET=clang COMPILER=clang++-10 CXXSTD=03,11,14,17,20 CXXFLAGS="-stdlib=libc++" LINKFLAGS="-stdlib=libc++"
+      addons:
+        apt:
+          packages:
+            - clang-10
+            - libc++-10-dev
+            - libc++abi-10-dev
+          sources:
+            - sourceline: "ppa:ubuntu-toolchain-r/test"
+            - sourceline: "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-10 main"
+              key_url: "https://apt.llvm.org/llvm-snapshot.gpg.key"
+
+# clang, OS X
+# Disabled because OS X builds are slow on Travis CI
+#    - os: osx
+#      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+#      osx_image: xcode9.4
+#
+#    - os: osx
+#      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,1z
+#      osx_image: xcode10.3
+#
+#    - os: osx
+#      env: TOOLSET=clang COMPILER=clang++ CXXSTD=03,11,14,17
+#      osx_image: xcode11.2
 
 install:
   - GIT_FETCH_JOBS=8
@@ -271,7 +379,7 @@ script:
   - |-
     echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
   - BUILD_JOBS=`(nproc || sysctl -n hw.ncpu) 2> /dev/null`
-  - ./b2 -j $BUILD_JOBS libs/detail/test toolset=$TOOLSET cxxstd=$CXXSTD
+  - ./b2 -j $BUILD_JOBS libs/detail/test toolset=$TOOLSET cxxstd=$CXXSTD ${CXXFLAGS:+cxxflags="$CXXFLAGS"} ${LINKFLAGS:+linkflags="$LINKFLAGS"}
 
 notifications:
   email:
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3e122d4..8ea9396 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,12 +3,9 @@
 # Distributed under the Boost Software License, Version 1.0.
 # See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt
 
-# Partial (add_subdirectory only) and experimental CMake support
-# Subject to change; please do not rely on the contents of this file yet.
+cmake_minimum_required(VERSION 3.5...3.20)
 
-cmake_minimum_required(VERSION 3.5)
-
-project(BoostDetail LANGUAGES CXX)
+project(boost_detail VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
 
 add_library(boost_detail INTERFACE)
 add_library(Boost::detail ALIAS boost_detail)
diff --git a/include/boost/detail/binary_search.hpp b/include/boost/detail/binary_search.hpp
index 3dca9b6..0591563 100644
--- a/include/boost/detail/binary_search.hpp
+++ b/include/boost/detail/binary_search.hpp
@@ -1,11 +1,11 @@
-// Copyright (c)  2000 David Abrahams. 
-// Distributed under the Boost Software License, Version 1.0. 
-// (See accompanying file LICENSE_1_0.txt or copy at 
+// Copyright (c)  2000 David Abrahams.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
-// 
+//
 // Copyright (c) 1994
 // Hewlett-Packard Company
-// 
+//
 // Permission to use, copy, modify, distribute and sell this software
 // and its documentation for any purpose is hereby granted without fee,
 // provided that the above copyright notice appear in all copies and
@@ -13,10 +13,10 @@
 // in supporting documentation.  Hewlett-Packard Company makes no
 // representations about the suitability of this software for any
 // purpose.  It is provided "as is" without express or implied warranty.
-// 
+//
 // Copyright (c) 1996
 // Silicon Graphics Computer Systems, Inc.
-// 
+//
 // Permission to use, copy, modify, distribute and sell this software
 // and its documentation for any purpose is hereby granted without fee,
 // provided that the above copyright notice appear in all copies and
@@ -24,22 +24,22 @@
 // in supporting documentation.  Silicon Graphics makes no
 // representations about the suitability of this software for any
 // purpose.  It is provided "as is" without express or implied warranty.
-// 
+//
 #ifndef BINARY_SEARCH_DWA_122600_H_
 # define BINARY_SEARCH_DWA_122600_H_
 
-# include <boost/detail/iterator.hpp>
 # include <utility>
+# include <iterator>
 
 namespace boost { namespace detail {
 
 template <class ForwardIter, class Tp>
 ForwardIter lower_bound(ForwardIter first, ForwardIter last,
-                             const Tp& val) 
+                             const Tp& val)
 {
-    typedef detail::iterator_traits<ForwardIter> traits;
-    
-    typename traits::difference_type len = boost::detail::distance(first, last);
+    typedef std::iterator_traits<ForwardIter> traits;
+
+    typename traits::difference_type len = std::distance(first, last);
     typename traits::difference_type half;
     ForwardIter middle;
 
@@ -62,9 +62,9 @@ template <class ForwardIter, class Tp, class Compare>
 ForwardIter lower_bound(ForwardIter first, ForwardIter last,
                               const Tp& val, Compare comp)
 {
-  typedef detail::iterator_traits<ForwardIter> traits;
+  typedef std::iterator_traits<ForwardIter> traits;
 
-  typename traits::difference_type len = boost::detail::distance(first, last);
+  typename traits::difference_type len = std::distance(first, last);
   typename traits::difference_type half;
   ForwardIter middle;
 
@@ -87,9 +87,9 @@ template <class ForwardIter, class Tp>
 ForwardIter upper_bound(ForwardIter first, ForwardIter last,
                            const Tp& val)
 {
-  typedef detail::iterator_traits<ForwardIter> traits;
+  typedef std::iterator_traits<ForwardIter> traits;
 
-  typename traits::difference_type len = boost::detail::distance(first, last);
+  typename traits::difference_type len = std::distance(first, last);
   typename traits::difference_type half;
   ForwardIter middle;
 
@@ -112,9 +112,9 @@ template <class ForwardIter, class Tp, class Compare>
 ForwardIter upper_bound(ForwardIter first, ForwardIter last,
                            const Tp& val, Compare comp)
 {
-  typedef detail::iterator_traits<ForwardIter> traits;
+  typedef std::iterator_traits<ForwardIter> traits;
 
-  typename traits::difference_type len = boost::detail::distance(first, last);
+  typename traits::difference_type len = std::distance(first, last);
   typename traits::difference_type half;
   ForwardIter middle;
 
@@ -137,9 +137,9 @@ template <class ForwardIter, class Tp>
 std::pair<ForwardIter, ForwardIter>
 equal_range(ForwardIter first, ForwardIter last, const Tp& val)
 {
-  typedef detail::iterator_traits<ForwardIter> traits;
+  typedef std::iterator_traits<ForwardIter> traits;
 
-  typename traits::difference_type len = boost::detail::distance(first, last);
+  typename traits::difference_type len = std::distance(first, last);
   typename traits::difference_type half;
   ForwardIter middle, left, right;
 
@@ -169,9 +169,9 @@ std::pair<ForwardIter, ForwardIter>
 equal_range(ForwardIter first, ForwardIter last, const Tp& val,
               Compare comp)
 {
-  typedef detail::iterator_traits<ForwardIter> traits;
+  typedef std::iterator_traits<ForwardIter> traits;
 
-  typename traits::difference_type len = boost::detail::distance(first, last);
+  typename traits::difference_type len = std::distance(first, last);
   typename traits::difference_type half;
   ForwardIter middle, left, right;
 
@@ -194,7 +194,7 @@ equal_range(ForwardIter first, ForwardIter last, const Tp& val,
     }
   }
   return std::pair<ForwardIter, ForwardIter>(first, first);
-}           
+}
 
 template <class ForwardIter, class Tp>
 bool binary_search(ForwardIter first, ForwardIter last,
diff --git a/include/boost/detail/catch_exceptions.hpp b/include/boost/detail/catch_exceptions.hpp
index 823ebd1..3db832a 100644
--- a/include/boost/detail/catch_exceptions.hpp
+++ b/include/boost/detail/catch_exceptions.hpp
@@ -20,13 +20,14 @@
 //  to reduce coupling to other boost libraries.
 #include <string>             // for string
 #include <new>                // for bad_alloc
+#include <ostream>            // for ostream
 #include <typeinfo>           // for bad_cast, bad_typeid
 #include <exception>          // for exception, bad_exception
 #include <stdexcept>          // for std exception hierarchy
+#include <boost/config.hpp>
 #include <boost/cstdlib.hpp>  // for exit codes
-#include <ostream>         // for ostream
 
-# if defined(__BORLANDC__) && (__BORLANDC__ <= 0x0551)
+# if defined(BOOST_BORLANDC) && (__BORLANDC__ <= 0x0551)
 #   define BOOST_BUILT_IN_EXCEPTIONS_MISSING_WHAT 
 # endif
 
diff --git a/include/boost/detail/is_sorted.hpp b/include/boost/detail/is_sorted.hpp
index 5ab32e5..84357f9 100644
--- a/include/boost/detail/is_sorted.hpp
+++ b/include/boost/detail/is_sorted.hpp
@@ -8,8 +8,7 @@
 #ifndef BOOST_DETAIL_SORTED_HPP
 #define BOOST_DETAIL_SORTED_HPP
 
-#include <boost/detail/iterator.hpp>
-
+#include <iterator>
 #include <functional>
 
 namespace boost {
@@ -31,23 +30,23 @@ inline Iterator is_sorted_until (Iterator first, Iterator last, Comp c) {
 
 template<class Iterator>
 inline Iterator is_sorted_until (Iterator first, Iterator last) {
-  typedef typename boost::detail::iterator_traits<Iterator>::value_type
+  typedef typename std::iterator_traits<Iterator>::value_type
     value_type;
 
-  typedef std::less<value_type> c; 
+  typedef std::less<value_type> c;
 
-  return ::boost::detail::is_sorted_until(first, last, c()); 
+  return ::boost::detail::is_sorted_until(first, last, c());
 }
 
 template<class Iterator, class Comp>
 inline bool is_sorted (Iterator first, Iterator last, Comp c) {
   return ::boost::detail::is_sorted_until(first, last, c) == last;
-} 
+}
 
 template<class Iterator>
 inline bool is_sorted (Iterator first, Iterator last) {
   return ::boost::detail::is_sorted_until(first, last) == last;
-} 
+}
 
 } // detail
 } // boost
diff --git a/include/boost/detail/named_template_params.hpp b/include/boost/detail/named_template_params.hpp
index e7cb079..7675c4e 100644
--- a/include/boost/detail/named_template_params.hpp
+++ b/include/boost/detail/named_template_params.hpp
@@ -11,9 +11,10 @@
 #ifndef BOOST_DETAIL_NAMED_TEMPLATE_PARAMS_HPP
 #define BOOST_DETAIL_NAMED_TEMPLATE_PARAMS_HPP
 
+#include <boost/config.hpp>
 #include <boost/type_traits/conversion_traits.hpp>
 #include <boost/type_traits/composite_traits.hpp> // for is_reference
-#if defined(__BORLANDC__)
+#if defined(BOOST_BORLANDC)
 #include <boost/type_traits/ice.hpp>
 #endif
 
@@ -57,7 +58,7 @@ namespace boost {
       };
     };
 
-#if defined(__BORLANDC__)
+#if defined(BOOST_BORLANDC)
     template <class UseDefault>
     struct choose_arg_or_default { typedef choose_arg type; };
     template <>
@@ -75,7 +76,7 @@ namespace boost {
     
     template <class Arg, class DefaultGen, class Base, class Traits>
     class resolve_default {
-#if defined(__BORLANDC__)
+#if defined(BOOST_BORLANDC)
       typedef typename choose_arg_or_default<typename is_default<Arg>::type>::type Selector;
 #else
       // This usually works for Borland, but I'm seeing weird errors in
diff --git a/include/boost/detail/utf8_codecvt_facet.ipp b/include/boost/detail/utf8_codecvt_facet.ipp
index f8f1cbc..f9e9deb 100644
--- a/include/boost/detail/utf8_codecvt_facet.ipp
+++ b/include/boost/detail/utf8_codecvt_facet.ipp
@@ -188,26 +188,17 @@ BOOST_UTF8_DECL int utf8_codecvt_facet::do_length(
 #if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
         throw()
 #endif
-{ 
-    // RG - this code is confusing!  I need a better way to express it.
-    // and test cases.
-
-    // Invariants:
-    // 1) last_octet_count has the size of the last measured character
-    // 2) char_count holds the number of characters shown to fit
-    // within the bounds so far (no greater than max_limit)
-    // 3) from_next points to the octet 'last_octet_count' before the
-    // last measured character.  
-    int last_octet_count=0;
-    std::size_t char_count = 0;
-    const char* from_next = from;
-    // Use "<" because the buffer may represent incomplete characters
-    while (from_next+last_octet_count <= from_end && char_count <= max_limit) {
-        from_next += last_octet_count;
-        last_octet_count = (get_octet_count(*from_next));
-        ++char_count;
+{
+    const char * from_next = from;
+    for (std::size_t char_count = 0u; char_count < max_limit && from_next < from_end; ++char_count) {
+        unsigned int octet_count = get_octet_count(*from_next);
+        // The buffer may represent incomplete characters, so terminate early if one is found
+        if (octet_count > static_cast<std::size_t>(from_end - from_next))
+            break;
+        from_next += octet_count;
     }
-    return static_cast<int>(from_next-from);
+
+    return static_cast<int>(from_next - from);
 }
 
 BOOST_UTF8_DECL unsigned int utf8_codecvt_facet::get_octet_count(
diff --git a/meta/libraries.json b/meta/libraries.json
index 5c1aa00..19784f5 100644
--- a/meta/libraries.json
+++ b/meta/libraries.json
@@ -19,7 +19,6 @@
         "Miscellaneous"
     ],
     "maintainers": [
-        "Beman Dawes <bdawes -at- acm.org>",
         "Robert Ramey <ramey -at- rrsd.com>",
         "Rene Rivera <grafikrobot -at- gmail.com>",
         "Andrey Semashev <andrey.semashev -at- gmail.com>"
diff --git a/test/Jamfile b/test/Jamfile
index b389925..c3f1aea 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -14,7 +14,8 @@ project detail/test
     <toolset>clang:<cxxflags>-ftemplate-depth-300
     <toolset>gcc:<cxxflags>-ftemplate-depth-300
     <toolset>gcc:<define>_STLP_DEBUG
-    <toolset>gcc:<define>_GLIBCXX_DEBUG
+    # Do not enable libstdc++ debug mode because of gcc 10.1 bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95289
+    # <toolset>gcc:<define>_GLIBCXX_DEBUG
     <toolset>darwin:<cxxflags>-ftemplate-depth-300
   ;
 
diff --git a/test/allocator_utilities_test.cpp b/test/allocator_utilities_test.cpp
index 2b06720..781d60b 100644
--- a/test/allocator_utilities_test.cpp
+++ b/test/allocator_utilities_test.cpp
@@ -5,14 +5,18 @@
 
 #include <boost/detail/allocator_utilities.hpp>
 #include <boost/static_assert.hpp>
-#include <cassert>
+#include <boost/core/allocator_access.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/type_traits/is_same.hpp>
+#include <memory>
 
 typedef std::allocator<int> std_int_allocator;
 typedef boost::detail::allocator::rebind_to<std_int_allocator, char>::type char_allocator;
 typedef boost::detail::allocator::rebind_to<char_allocator, int>::type int_allocator;
 typedef boost::detail::allocator::rebind_to<int_allocator, char>::type char_allocator2;
 
-int main() {
+int main()
+{
     BOOST_STATIC_ASSERT((!boost::is_same<char_allocator, int_allocator>::value));
     BOOST_STATIC_ASSERT((boost::is_same<char_allocator, char_allocator2>::value));
 
@@ -24,17 +28,19 @@ int main() {
 
     // Check allocate works okay
     {
-        char_allocator::pointer p = a2.allocate(10);
-        assert(p);
+        boost::allocator_pointer<char_allocator>::type p = a2.allocate(10);
+        BOOST_TEST(!!p);
         a2.deallocate(p, 10);
     }
 
     // Try using the standalone construct/destroy
     {
-        int_allocator::pointer p2 = a3.allocate(1);
+        boost::allocator_pointer<int_allocator>::type p2 = a3.allocate(1);
         boost::detail::allocator::construct(p2, 25);
-        assert(*p2 == 25);
+        BOOST_TEST(*p2 == 25);
         boost::detail::allocator::destroy(p2);
         a3.deallocate(p2, 1);
     }
+
+    return boost::report_errors();
 }
diff --git a/test/binary_search_test.cpp b/test/binary_search_test.cpp
index aeecfc0..ee4d6d2 100644
--- a/test/binary_search_test.cpp
+++ b/test/binary_search_test.cpp
@@ -3,18 +3,19 @@
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
+#include <boost/detail/binary_search.hpp>
 #include <vector>
 #include <string>
 #include <memory>
 #include <climits>
 #include <iostream>
-#include <cassert>
+#include <cstddef>
 #include <stdlib.h> // for rand(). Would use cstdlib but VC6.4 doesn't put it in std::
 #include <list>
+#include <utility>
 #include <algorithm>
-#include <boost/detail/binary_search.hpp>
 #include <boost/detail/workaround.hpp>
-#include <cstddef>
+#include <boost/core/lightweight_test.hpp>
 
 #if defined(__SGI_STL_PORT) ? defined(__SGI_STL_OWN_IOSTREAMS) : (!defined(__GNUC__) || __GNUC__ > 2)
 # define USE_SSTREAM
@@ -32,7 +33,7 @@ namespace {
 struct mystring : std::string
 {
     typedef std::string base;
-    
+
     mystring(std::string const& x)
         : base(x) {}
 };
@@ -180,13 +181,13 @@ template <class Sequence, class Compare>
 void test_loop(Sequence& x, Compare cmp, unsigned long test_count)
 {
     typedef typename Sequence::const_iterator const_iterator;
-    
+
     for (unsigned long i = 0; i < test_count; ++i)
     {
         random_sorted_sequence(x);
         const const_iterator start = x.begin();
         const const_iterator finish = x.end();
-        
+
         unsigned key = random_number();
         const const_iterator l = searches<Compare>::lower_bound(start, finish, key, cmp);
         const const_iterator u = searches<Compare>::upper_bound(start, finish, key, cmp);
@@ -204,38 +205,40 @@ void test_loop(Sequence& x, Compare cmp, unsigned long test_count)
 
             if (p == u)
             {
-                assert(found_l);
+                BOOST_TEST(found_l);
                 found_u = true;
             }
 
             unsigned value = to_int(*p);
-            assert(value >= last_value);
+            BOOST_TEST(value >= last_value);
             last_value = value;
 
             if (!found_l)
             {
                 ++index;
-                assert(to_int(*p) < key);
+                BOOST_TEST(to_int(*p) < key);
             }
             else if (!found_u)
             {
                 ++count;
-                assert(to_int(*p) == key);
+                BOOST_TEST(to_int(*p) == key);
             }
             else
-                assert(to_int(*p) > key);
+            {
+                BOOST_TEST(to_int(*p) > key);
+            }
         }
-        assert(found_l || l == finish);
-        assert(found_u || u == finish);
+        BOOST_TEST(found_l || l == finish);
+        BOOST_TEST(found_u || u == finish);
 
         std::pair<const_iterator, const_iterator>
             range = searches<Compare>::equal_range(start, finish, key, cmp);
-        assert(range.first == l);
-        assert(range.second == u);
+        BOOST_TEST(range.first == l);
+        BOOST_TEST(range.second == u);
 
         bool found = searches<Compare>::binary_search(start, finish, key, cmp);
         (void)found;
-        assert(found == (u != l));
+        BOOST_TEST(found == (u != l));
         std::cout << "found " << count << " copies of " << key << " at index " << index << "\n";
     }
 }
@@ -256,5 +259,6 @@ int main()
     std::cout << "=== testing bidirectional iterators with compare: ===\n";
     test_loop(y, cmp(), 25);
     std::cerr << "******TEST PASSED******\n";
-    return 0;
+
+    return boost::report_errors();
 }
diff --git a/test/blank_test.cpp b/test/blank_test.cpp
index c1cf033..721aa58 100644
--- a/test/blank_test.cpp
+++ b/test/blank_test.cpp
@@ -5,28 +5,33 @@
 
 #include <boost/blank.hpp>
 #include <boost/static_assert.hpp>
-#include <cassert>
-
+#include <boost/core/lightweight_test.hpp>
+#include <boost/type_traits/is_pod.hpp>
+#include <boost/type_traits/is_empty.hpp>
+#include <boost/type_traits/is_stateless.hpp>
 #if !defined(BOOST_NO_IOSTREAM)
 #include <sstream>
 #endif
 
-int main() {
+int main()
+{
     BOOST_STATIC_ASSERT((boost::is_pod<boost::blank>::value));
     BOOST_STATIC_ASSERT((boost::is_empty<boost::blank>::value));
     BOOST_STATIC_ASSERT((boost::is_stateless<boost::blank>::value));
 
     boost::blank b1,b2;
-    assert(b1 == b2);
-    assert(b1 <= b2);
-    assert(b1 >= b2);
-    assert(!(b1 != b2));
-    assert(!(b1 < b2));
-    assert(!(b1 > b2));
+    BOOST_TEST(b1 == b2);
+    BOOST_TEST(b1 <= b2);
+    BOOST_TEST(b1 >= b2);
+    BOOST_TEST(!(b1 != b2));
+    BOOST_TEST(!(b1 < b2));
+    BOOST_TEST(!(b1 > b2));
 
 #if !defined(BOOST_NO_IOSTREAM)
     std::stringstream s;
     s << "(" << b1 << ")";
-    assert(s.str() == "()");
+    BOOST_TEST(s.str() == "()");
 #endif
+
+    return boost::report_errors();
 }
diff --git a/test/is_sorted_test.cpp b/test/is_sorted_test.cpp
index f88d91c..58cb31c 100644
--- a/test/is_sorted_test.cpp
+++ b/test/is_sorted_test.cpp
@@ -5,11 +5,11 @@
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 
+#include <boost/detail/is_sorted.hpp>
 #include <iostream>
 #include <boost/config.hpp>
 #include <boost/array.hpp>
-#include <boost/detail/is_sorted.hpp>
-#include <boost/detail/lightweight_test.hpp>
+#include <boost/core/lightweight_test.hpp>
 
 template<class T>
 struct tracking_less {
diff --git a/test/numeric_traits_test.cpp b/test/numeric_traits_test.cpp
index c22cc6f..197f61f 100644
--- a/test/numeric_traits_test.cpp
+++ b/test/numeric_traits_test.cpp
@@ -154,6 +154,12 @@ template <> struct stream_as<signed char>  {
     typedef unsigned char t1; typedef unsigned t2;
 };
 
+// C++20 ostream has deleted operator<< for wchar_t
+template <> struct stream_as<wchar_t> {
+    typedef unsigned int t1;
+    typedef unsigned int t2;
+};
+
 #if defined(BOOST_MSVC_STD_ITERATOR) // No intmax streaming built-in
 
 // With this library implementation, __int64 and __uint64 get streamed as strings