Below are the changes for the current release.
See the CHANGES file for changes in older releases.
See the RELEASENOTES file for a summary of changes in each release.
Issue # numbers mentioned below can be found on Github. For more details, add
the issue number to the end of the URL: https://github.com/swig/swig/issues/

Version 4.0.0 (in progress)
===========================

2017-06-03: wsfulton
            Fix %import on a file containing a file scope %fragment forced inclusion to not
            generate the fragment contents as %import should not result in code being generated.
            The behaviour is now the same as importing code insertion blocks.
            Wrapping FileC.i in the following example will result in no generated code, whereas
            previously "#include <limits.h>" was generated:

              // FileA.i
              %fragment("<limits.h>", "header") %{
                #include <limits.h>
              %}

              %{
                #include <stdio.h>
              %}
              %fragment("<limits.h>");

              // FileC.i
              %import "FileA.i"

            *** POTENTIAL INCOMPATIBILITY ***

2017-05-26: Volker Diels-Grabsch, vadz
            [Java] Implement java.util.List<> for std::vector. This notably allows to
            iterate over wrapped vectors in a natural way.

2017-05-25: asibross
            [Java] #370 #417 Missing smart pointer handling in Java director extra methods
            swigReleaseOwnership() and swigTakeOwnership().

2017-05-23: wsfulton
            [Java] #230 #759 Fix Java shared_ptr and directors for derived classes java compilation
            error.

            For shared_ptr proxy proxy classes, add a protected method swigSetCMemOwn for modifying
            the swigCMemOwn and swigCMemOwnDerived member variables which are used by various other
            methods for controlling memory ownership.

2017-05-21: Sghirate
            [Java, C#, D] #449 Remove unnecessary use of dynamic_cast in directors to enable
            non-RTTI compilation.

2017-05-21: wsfulton
            [Python] #993 Fix handling of default -ve unsigned values, such as:
              void f(unsigned = -1U);

2017-05-20: jschueller
            [Python] #991 Fix E731 PEP8 warning: do not assign a lambda expression

2017-05-16: nihal95
            [PHP] Add %pragma version directive to allow the version of the
            extension to be set.  Patch #970, fixes #360.

2017-05-13: yag00
            Patch #975 - Add support for noexcept on director methods.

2017-04-27: redbrain
            Issue #974, Patch #976 - Fix preprocessor handling of macros with commas in a comment.

2017-04-25: jleveque
            [Lua] #959 - Fix Visual Studio C4244 conversion warnings in Lua wrappers.

2017-04-21: tamuratak
            [Ruby] #964 - Add shared_ptr director typemaps.

2017-04-20: wsfulton
            [Ruby] #586, #935 Add assert for invalid NULL type parameter when calling SWIG_Ruby_NewPointerObj.

2017-04-20: tamuratak
            [Ruby] #930, #937 - Fix containers of std::shared_ptr.
            Upcasting, const types (eg vector<shared_ptr<const T>>) and NULL/nullptr support added.

2017-04-12: smarchetto
            [Scilab] New parameter targetversion to specify the Scilab target version (5, 6, ..) for code generation
            With Scilab 6 target specified, identifier names truncation is disabled (no longer necessary)

2017-02-29: tamuratak
            [Ruby] #917 - Add Enumerable module to all container class wrappers. It was missing
            for std::list, std::multiset, std::unordered_multiset and std::unordered_map.

2017-03-24: tamuratak
            [Ruby] Fix #939 - Wrapping std::vector<bool> fix due to incorrect null checks
            on VALUE obj.

2017-03-17: vadz
            [C#] #947 Add support for std::complex<T>

2017-03-17: wsfulton
            [Go] Fix handling of typedef'd function pointers and typedef'd member function pointers
            such as:

              typedef int (*FnPtr_td)(int, int);
              int do_op(int x, int y, FnPtr_td op);

2017-03-16: wsfulton
            Add support for member const function pointers such as:

              int fn(short (Funcs::* parm)(bool)) const;

            Also fix parsing of references/pointers and qualifiers to member
            pointers such as:

              int fn(short (Funcs::* const parm)(bool));
              int fn(short (Funcs::* & parm)(bool));

2017-03-10: wsfulton
            Extend C++11 alternate function syntax parsing to support const and noexcept, such as:

              auto sum1(int x, int y) const -> int { return x + y; }
              auto sum2(int x, int y) noexcept -> int { return x + y; }

2017-02-27: assambar
            [C++11] Extend parser to support throw specifier in combination
            with override and/or final.

2017-02-10: tamuratak
            [Ruby] #883 - Add support for C++11 hash tables:
              std::unordered_map
              std::unordered_set
              std::unordered_multimap
              std::unordered_multiset

2017-02-08: jcsharp
            [C#] #887 Improve std::vector<T> wrapper constructors -
            Replace constructor taking ICollection with IEnumerable and also add IEnumerable<T>
            constructor to avoid the boxing and unboxing overhead of the original constructor,
            when the type parameter is a value type.