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 4.2.0 (in progress)
===========================

2022-12-29: wsfulton
            #1863 Syntax error fixes parsing more elaborate parameter pack arguments that are
            used in function pointers, member function pointers:

              template <typename... V> struct VariadicParms {
                void ParmsFuncPtrPtr(int (*)(V*...)) {}
                void ParmsFuncPtrPtrRef(int (*)(V*&...)) {}
                void ParmsFuncPtrPtrRValueRef(int (*)(V*&&...)) {}
                void ParmsFuncPtrRef(int (*)(V&...)) {}
                void ParmsFuncPtrRValueRef(int (*)(V&&...)) {}

                void ParmsMemFuncPtrPtr(int (KlassMemFuncs::*)(V*...)) {}
                void ParmsMemFuncPtrPtrRef(int (KlassMemFuncs::*)(V*&...)) {}
                void ParmsMemFuncPtrPtrRValueRef(int (KlassMemFuncs::*)(V*&&...)) {}
                void ParmsMemFuncPtrRef(int (KlassMemFuncs::*)(V&...)) {}
                void ParmsMemFuncPtrRValueRef(int (KlassMemFuncs::*)(V&&...)) {}
              };

              %template(VariadicParms0) VariadicParms<>;
              %template(VariadicParms1) VariadicParms<A>;

            Also in various other places such as within noexcept specifiers:

              template<typename T, typename... Args>
              void emplace(Args &&... args) noexcept(
                  std::is_nothrow_constructible<T, Args &&...>::value);

2022-12-27: wsfulton
            Fix instantiation of variadic class templates containing parameter pack arguments that
            are function pointers.

              template <typename... V> struct VariadicParms {
                void ParmsFuncPtrVal(int (*)(V...)) {}
              };

              %template(VariadicParms0) VariadicParms<>;
              %template(VariadicParms1) VariadicParms<A>;

2022-12-23: wsfulton
            #1863 Fix syntax error parsing variadic templates containing parameter pack arguments that
            are function pointers.

2022-12-22: wsfulton
            Complete support for C++11 variadic templates. Support was previously limited
            to just one template parameter. Now zero or more template parameters are supported.

2022-12-06: wsfulton
            #1636 Fix syntax error for misplaced Doxygen comment after struct/class member.
            Fix syntax error using Doxygen member groups syntax, "///*}", when used after
            final struct/class member.

2022-12-05: wsfulton
            #2023 Fix garbled Doxygen post comments in parameter lists.
            Fix syntax error parsing a trailing Doxygen comment in parameter lists.

2022-12-03: wsfulton
            #1609 Fix syntax error parsing of Doxygen comments after last enum item.

2022-12-03: wsfulton
            #1715 Fix syntax error parsing of unconventionally placed Doxygen post
            comments for enum items.

2022-12-02: wsfulton
            #624 #1021 Improved template template parameters support. Previously, specifying more
            than one simple template template parameter resulted in a parse error. Now
            multiple template template parameters are working including instantiation with
            %template. Example:

              template <template<template<class> class, class> class Op, template<class> class X, class Y>
              class C { ... };

2022-11-26: wsfulton
            #1589 #1590 Slightly better decltype() support for expressions, such as:

              int i,j;
              ...  decltype(i+j) ...
              ...  decltype(&i) ...

            These result in a warning for non-trivial expressions which SWIG cannot evaluate:

              Warning 344: Unable to deduce decltype for 'i+j'.

            See 'Type Inference' in CPlusPlus.html for workarounds.

2022-11-22: wsfulton
            #1037 Fix seg fault handling template parameter expressions containing '<='
            or '>='.

2022-11-18: wsfulton
            Duplicate class template instantiations via %template now issue a warning and are ignored.

                %template(Aint) A<int>;
                %template(Aint2) A<int>; // Now ignored and issues a warning

            example.i:7: Warning 404: Duplicate template instantiation of 'A< int >' with name 'Aint2' ignored,
            example.i:6: Warning 404: previous instantiation of 'A< int >' with name 'Aint'.

            A single empty template instantiation before a named instantiation is the one exception
            for allowing duplicate template instantiations as the empty template instantation does not
            create a wrapper for the template, it merely adds the instantiation into SWIG's internal
            type system.
            Duplicate empty template instantiations are quietly ignored.

                %template() B<int>;
                %template(Bint) B<int>; // OK

                %template() C<int>;
                %template() C<int>; // Quietly ignored now
                %template(Cint) C<int>; // OK

            Note that default template parameters are considered when looking for duplicates such as:

                template <typename T, typename U = short> struct D {};
                %template(Dint) D<int>;
                %template(Dintshort) D<int, short>;

            example.i:7: Warning 404: Duplicate template instantiation of 'D< int,short >' with name 'Dintshort' ignored,
            example.i:6: Warning 404: previous instantiation of 'D< int >' with name 'Dint'.

            Note that the following always was ignored, but that was because the chosen name was a
            duplicate rather than the template being a duplicate:

                %template(Eint) E<int>;
                %template(Eint) E<int>; // Always has been ignored as a redefined identifier

            The old warning was:

            example.i:7: Warning 302: Identifier 'Eint' redefined (ignored) (Renamed from 'E< int >'),
            example.i:6: Warning 302: previous definition of 'Eint' (Renamed from 'E< int >').

	    *** POTENTIAL INCOMPATIBILITY ***