Changes 1.63.0:

Atomic:
* Added the static constant atomic<T>::is_always_lock_free for conformance with C++17. The constant indicates that the given specialization always provides lock-free implementation of atomic operations.
* Improved support of Oracle Studio on x86 targets.

Container:
* Fixed bugs

Context:
* 11687 Xcode (Apple clang) and thread_local
* 12114 context does not preserve fpu context on ios arm64 devices (fixed for other architecturs too)
* 12411 fpu registers not preserved with O2 optimizations in Visual Studio (fixed for other architecturs too)
* 12551 building boost on arm64 causes error: unknown directive
* reduced signatur for ontop-functions
* unit-test for private fcontext-API
* performance-test for ucontext and fcontext fixed

Fiber:
* unbounded_channel and bounded_channel marked as deprecated
* new classes buffered_channel and unbuffered_channel
* performance improved

Fusion:
* Fixed fusion::vector buggy constructors (Thanks to Lee Clagett).
* BOOST_FUSION_ADAPT* and BOOST_FUSION_DEFINE* now allow empty structures. (6592)
* BOOST_FUSION_DEFINE* allows move constructor and assignment. (10099)
* Adaptor for std::array (Thanks to Mateusz ��oskot). (8241)
* Fixed returning temporary variable warnings on MSVC.

Geometry:
* Intersection: take care that output is valid (work in progres, not yet finished - but more is valid)
* 12289 Avoid warning/compilation error for std::cout
* 12412 Invalid result of covered_by() with geographic Points and Boxes
* 12413 rtree::remove() not working properly with geographic Points

Hash:
* Fixed some warnings.

Interprocess:
* Fixed bugs

Intrusive:
* Fixed bugs

Lexical Cast:
* Fixed issue found by -fsanitize=undefined 21

Log:
* Removed the previously deprecated type_info_wrapper.
* Added a way to access the current file name from the text file sink backend. The file name can be obtained with the get_current_file_name method.
* Bug fixes

Metaparse:
* Improved the implementation of BOOST_METAPARSE_STRING

Move:
* Improved experimental adaptive sort algorithm performance
* Activate BOOST_MOVE_FORCEINLINE

Optional:
* Added two new in-place constructors. They work similarly to emplace() functions: they initialize the contained value by perfect-forwarding the obtained arguments. One constructor always initializes the contained value, the other based on a boolean condition.
* Syntax o = {} now correctly un-initializes an optional, just like in std::optional.
* Fixed optional<optional<T>&> initialization. (12203)
* Optional constructors are sfinae-friendly. This fixes interaction with std::tuple. (12563)

Phoenix:
* Most of modules now support C++11 variadic templates.
* Fixed type deduction failure with result type.
* Suppress unused warnings.
* Fixed too few arguments error on binary math functions.
* Added workarounds for older compiler.

Python:
* Added (basic) support for C++11 (std::shared_ptr, std::unique_ptr)
* Incorporated an extension API to wrap NumPy
* Removed obsolete bits and pieces

Test:
* Boost.test v3.4 see the Change log section for more details.
* New feature: per_element and lexicographic modifiers of BOOST_TEST can also be applied to string comparison
* Breaking change: colons that appear in test case names are replaced with underscores
* Bug fixes

TypeIndex:
* Added runtime_cast to the library as an emulation of dynamic_cast. Thanks to Chris Glover for the implementation. See runtime_cast reference for more info.
* Internals of the CTTI were made more platform independant, due to change of the std::size_t type to unsigned int.

Units:
* Fix inspection warnings
* updated physico-chemical constants to CODATA 2014 values
* define biot correctly as 10 Ampere

Unordered:
* Fix an exception safety issue in assignment.
* Use std::allocator_traits where available, and support modern style rebind (12459).
* Add some allocator aware constructors.
* Use the hint iterator in emplace_hint.
* Fixed some warnings.

(adam)