diff --git a/configure b/configure
index 2f72f2abb1..5994e3d50f 100755
--- a/configure
+++ b/configure
@@ -1119,6 +1119,7 @@ enable_std_containers_compat
 enable_std_iostreams
 enable_std_string
 enable_std_string_conv_in_wxstring
+enable_unsafe_conv_in_wxstring
 enable_unicode
 enable_utf8
 enable_utf8only
@@ -2057,6 +2058,7 @@ Optional Features:
   --enable-std_iostreams  use standard C++ stream classes
   --enable-std_string     use standard C++ string classes
  --enable-std_string_conv_in_wxstring     provide implicit conversion to std::string in wxString
+ --disable-unsafe_conv_in_wxstring        disable unsafe implicit conversions in wxString
   --disable-unicode       compile without Unicode support
   --enable-utf8           use UTF-8 representation for strings (Unix only)
   --enable-utf8only       only support UTF-8 locales in UTF-8 build (Unix only)
@@ -5469,6 +5471,35 @@ fi
           eval "$wx_cv_use_std_string_conv_in_wxstring"
 
 
+          enablestring=disable
+          defaultval=
+          if test -z "$defaultval"; then
+              if test x"$enablestring" = xdisable; then
+                  defaultval=yes
+              else
+                  defaultval=no
+              fi
+          fi
+
+          # Check whether --enable-unsafe_conv_in_wxstring was given.
+if test "${enable_unsafe_conv_in_wxstring+set}" = set; then :
+  enableval=$enable_unsafe_conv_in_wxstring;
+                          if test "$enableval" = yes; then
+                            wx_cv_use_unsafe_conv_in_wxstring='wxUSE_UNSAFE_WXSTRING_CONV=yes'
+                          else
+                            wx_cv_use_unsafe_conv_in_wxstring='wxUSE_UNSAFE_WXSTRING_CONV=no'
+                          fi
+
+else
+
+                          wx_cv_use_unsafe_conv_in_wxstring='wxUSE_UNSAFE_WXSTRING_CONV=${'DEFAULT_wxUSE_UNSAFE_WXSTRING_CONV":-$defaultval}"
+
+fi
+
+
+          eval "$wx_cv_use_unsafe_conv_in_wxstring"
+
+
           enablestring=disable
           defaultval=
           if test -z "$defaultval"; then
@@ -32527,6 +32558,11 @@ if test "$wxUSE_STD_STRING_CONV_IN_WXSTRING" = "yes"; then
 
 fi
 
+if test "$wxUSE_UNSAFE_WXSTRING_CONV" = "yes"; then
+  $as_echo "#define wxUSE_UNSAFE_WXSTRING_CONV 1" >>confdefs.h
+
+fi
+
 if test "$wxUSE_STDPATHS" = "yes"; then
   $as_echo "#define wxUSE_STDPATHS 1" >>confdefs.h
 
diff --git a/configure.in b/configure.in
index 99e15b4784..75ba90ec7f 100644
--- a/configure.in
+++ b/configure.in
@@ -642,6 +642,7 @@ WX_ARG_ENABLE(std_containers_compat, [  --enable-std_containers_compat     use s
 WX_ARG_ENABLE(std_iostreams, [  --enable-std_iostreams  use standard C++ stream classes], wxUSE_STD_IOSTREAM)
 WX_ARG_ENABLE(std_string,    [  --enable-std_string     use standard C++ string classes], wxUSE_STD_STRING)
 WX_ARG_ENABLE(std_string_conv_in_wxstring, [ --enable-std_string_conv_in_wxstring     provide implicit conversion to std::string in wxString], wxUSE_STD_STRING_CONV_IN_WXSTRING)
+WX_ARG_DISABLE(unsafe_conv_in_wxstring,     [ --disable-unsafe_conv_in_wxstring        disable unsafe implicit conversions in wxString], wxUSE_UNSAFE_WXSTRING_CONV)
 WX_ARG_DISABLE(unicode,      [  --disable-unicode       compile without Unicode support], wxUSE_UNICODE)
 WX_ARG_ENABLE_PARAM(utf8,    [  --enable-utf8           use UTF-8 representation for strings (Unix only)], wxUSE_UNICODE_UTF8)
 WX_ARG_ENABLE(utf8only,      [  --enable-utf8only       only support UTF-8 locales in UTF-8 build (Unix only)], wxUSE_UNICODE_UTF8_LOCALE)
@@ -5665,6 +5666,10 @@ if test "$wxUSE_STD_STRING_CONV_IN_WXSTRING" = "yes"; then
   AC_DEFINE(wxUSE_STD_STRING_CONV_IN_WXSTRING)
 fi
 
+if test "$wxUSE_UNSAFE_WXSTRING_CONV" = "yes"; then
+  AC_DEFINE(wxUSE_UNSAFE_WXSTRING_CONV)
+fi
+
 if test "$wxUSE_STDPATHS" = "yes"; then
   AC_DEFINE(wxUSE_STDPATHS)
 fi
diff --git a/docs/changes.txt b/docs/changes.txt
index a8630936dd..124e2befb8 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -69,6 +69,7 @@ INCOMPATIBLE CHANGES SINCE 3.1.0:
 All:
 
 - Add wxSecretStore for storing passwords using the OS-provided facilities.
+- Add support for compiling application code with wxNO_UNSAFE_WXSTRING_CONV.
 - Add support for the micro version (third component) to OS and toolkit version
   functions. See wxGetOsVersion(), wxPlatformInfo, and wxAppTraits.
 - wxLogInfo() now logs messages if the log level is high enough, even without
diff --git a/docs/doxygen/mainpages/const_cpp.h b/docs/doxygen/mainpages/const_cpp.h
index edadff7088..1756d18a82 100644
--- a/docs/doxygen/mainpages/const_cpp.h
+++ b/docs/doxygen/mainpages/const_cpp.h
@@ -243,6 +243,59 @@ the project that uses wxWidgets to the same value as the @c CFG variable in
 order for the correct @c wx/setup.h file to automatically be included for that
 configuration.
 
+
+@section page_cppconst_compatibility Compatibility Macros
+
+wxWidgets always tries to preserve source backwards compatibility, however
+sometimes existing symbols may need to be removed. Except in exceedingly rare
+cases, this happens in several steps: first, the symbol is marked as
+deprecated, so that using it results in a warning when using the common
+compilers (e.g. any non-ancient version of MSVC, gcc or clang) in some
+wxWidgets release @c x.y. It can still be used, however the warnings indicate
+all the places in your code which will need to be updated in the future. If
+your code doesn't use any deprecated symbols or you have already fixed all
+their occurrences, you may change @c WXWIN_COMPATIBILITY_x_y to 0 to ensure
+they can't be used -- however its default value is still 1 at this time.
+
+At some point in the future, the next stable wxWidgets release @c x.y+2 changes
+the default @c WXWIN_COMPATIBILITY_x_y value to 0, meaning that now the symbol
+becomes unavailable by default and if you still want to be able to compile the
+code using it, you need to explicitly change @c WXWIN_COMPATIBILITY_x_y to 1
+when building the library.
+
+And, finally, the symbol is completely removed from the library in the next
+stable version after this, i.e. @c x.y+4. @c WXWIN_COMPATIBILITY_x_y itself is
+removed as well at this time, as it is not useful any longer.
+
+According to this general rule, currently, i.e. in wxWidgets 3.2, the following
+two symbols are defined: @c WXWIN_COMPATIBILITY_2_8, as 0, and @c
+WXWIN_COMPATIBILITY_3_0, as 1. Please see @ref overview_backwardcompat for even
+more details.
+
+@beginDefList
+@itemdef{WXWIN_COMPATIBILITY_2_8,
+         defined as 0 by default meaning that symbols existing in wxWidgets 2.8
+         but deprecated in 3.0 release are not available by default. It can be
+         changed to 1 to make them available, but it is strongly recommended to
+         update the code using them instead.}
+@itemdef{WXWIN_COMPATIBILITY_3_0,
+         defined as 1 by default meaning that symbols existing in wxWidgets 3.0
+         but deprecated since then are still available. It can be changed to 1
+         to ensure that no deprecated symbols are used accidentally.}
+@itemdef{wxDIALOG_UNIT_COMPATIBILITY,
+         wxMSW-specific setting which can be set to 1 to make
+         wxWindow::GetCharWidth() and wxWindow::GetCharHeight() more compatible
+         with old wxWidgets versions. Changing it is not recommended.}
+@itemdef{wxUSE_UNSAFE_WXSTRING_CONV,
+         this option determines if unsafe implicit conversions of wxString to
+         @c char* or @c std::string (depending on whether @c wxUSE_STL is 0 or
+         1) are defined. It is set to 1 by default for compatibility reasons,
+         however it is recommended to set it to 0 for the new projects. See
+         also @c wxNO_UNSAFE_WXSTRING_CONV below for an alternative way of
+         disabling these unsafe conversions not requiring rebuilding the
+         library.}
+@endDefList
+
 @section page_cppconst_miscellaneous Miscellaneous
 
 @beginDefList
@@ -281,6 +334,15 @@ configuration.
         don't include compiler flags needed for multithreaded code generation. This
         implies that wxUSE_THREADS is 0 and also that other (non-wx-based) threading
         packages cannot be used neither.}
+@itemdef{wxNO_UNSAFE_WXSTRING_CONV,
+        this symbol is not defined by wxWidgets itself, but can be defined by
+        the applications using the library to disable unsafe implicit
+        conversions in wxString class. This is especially useful when using
+        standard build of the library, e.g. installed by the system package
+        manager under Unix, which is compiled with @c wxUSE_UNSAFE_WXSTRING_CONV
+        set to 1 for compatibility reasons as @c -DwxNO_UNSAFE_WXSTRING_CONV
+        can be used only compiling the application code, without rebuilding the
+        library. Support for this option appeared in wxWidgets 3.1.1.}
 @itemdef{WXMAKINGDLL_XXX,
         used internally and defined when building the
         library @c XXX as a DLL; when a monolithic wxWidgets build is used only a
diff --git a/include/wx/android/setup.h b/include/wx/android/setup.h
index 9e8c35e644..3249bd429f 100644
--- a/include/wx/android/setup.h
+++ b/include/wx/android/setup.h
@@ -54,6 +54,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1431,9 +1443,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/include/wx/chkconf.h b/include/wx/chkconf.h
index 2722a6b6a8..3fee662977 100644
--- a/include/wx/chkconf.h
+++ b/include/wx/chkconf.h
@@ -373,6 +373,14 @@
 #   endif
 #endif /* !defined(wxUSE_UNICODE) */
 
+#ifndef wxUSE_UNSAFE_WXSTRING_CONV
+#   ifdef wxABORT_ON_CONFIG_ERROR
+#       error "wxUSE_UNSAFE_WXSTRING_CONV must be defined, please read comment near the top of this file."
+#   else
+#       define wxUSE_UNSAFE_WXSTRING_CONV 0
+#   endif
+#endif /* !defined(wxUSE_UNSAFE_WXSTRING_CONV) */
+
 #ifndef wxUSE_URL
 #   ifdef wxABORT_ON_CONFIG_ERROR
 #       error "wxUSE_URL must be defined, please read comment near the top of this file."
diff --git a/include/wx/gtk/setup0.h b/include/wx/gtk/setup0.h
index d66b698478..b99ba3ce3e 100644
--- a/include/wx/gtk/setup0.h
+++ b/include/wx/gtk/setup0.h
@@ -55,6 +55,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1432,9 +1444,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/include/wx/motif/setup0.h b/include/wx/motif/setup0.h
index cf922bc5a8..9c9fb35f33 100644
--- a/include/wx/motif/setup0.h
+++ b/include/wx/motif/setup0.h
@@ -55,6 +55,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1432,9 +1444,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/include/wx/msw/setup0.h b/include/wx/msw/setup0.h
index 6b4d8bc7dc..ca1579941e 100644
--- a/include/wx/msw/setup0.h
+++ b/include/wx/msw/setup0.h
@@ -55,6 +55,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
diff --git a/include/wx/osx/setup0.h b/include/wx/osx/setup0.h
index 4ba8eb2bf2..4a1f5d1604 100644
--- a/include/wx/osx/setup0.h
+++ b/include/wx/osx/setup0.h
@@ -56,6 +56,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1433,9 +1445,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/include/wx/setup_inc.h b/include/wx/setup_inc.h
index ca8f94bd50..b8d5e21b32 100644
--- a/include/wx/setup_inc.h
+++ b/include/wx/setup_inc.h
@@ -51,6 +51,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1428,9 +1440,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/include/wx/string.h b/include/wx/string.h
index 7b39add2b1..3441a7f7d6 100644
--- a/include/wx/string.h
+++ b/include/wx/string.h
@@ -1263,7 +1263,9 @@ public:
     // they conflict with the implicit conversions to "const char/wchar_t *"
     // which we use for backwards compatibility but do provide them if
     // explicitly requested.
+#if wxUSE_UNSAFE_WXSTRING_CONV && !defined(wxNO_UNSAFE_WXSTRING_CONV)
   operator wxStringToStdStringRetType() const { return ToStdString(); }
+#endif // wxUSE_UNSAFE_WXSTRING_CONV
   operator wxStringToStdWstringRetType() const { return ToStdWstring(); }
 #endif // wxUSE_STD_STRING_CONV_IN_WXSTRING
 
@@ -1517,13 +1519,16 @@ public:
     // messages for the code which relies on implicit conversion to char* in
     // STL build
 #if !wxUSE_STD_STRING_CONV_IN_WXSTRING
-    operator const char*() const { return c_str(); }
     operator const wchar_t*() const { return c_str(); }
 
+#if wxUSE_UNSAFE_WXSTRING_CONV && !defined(wxNO_UNSAFE_WXSTRING_CONV)
+    operator const char*() const { return c_str(); }
     // implicit conversion to untyped pointer for compatibility with previous
     // wxWidgets versions: this is the same as conversion to const char * so it
     // may fail!
     operator const void*() const { return c_str(); }
+#endif // wxUSE_UNSAFE_WXSTRING_CONV && !defined(wxNO_UNSAFE_WXSTRING_CONV)
+
 #endif // !wxUSE_STD_STRING_CONV_IN_WXSTRING
 
     // identical to c_str(), for MFC compatibility
diff --git a/include/wx/univ/setup0.h b/include/wx/univ/setup0.h
index 42f75c700d..3a0f7d86e2 100644
--- a/include/wx/univ/setup0.h
+++ b/include/wx/univ/setup0.h
@@ -54,6 +54,18 @@
 // Recommended setting: 0
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+// Provide unsafe implicit conversions in wxString to "const char*" or
+// "std::string" (depending on wxUSE_STD_STRING_CONV_IN_WXSTRING value).
+//
+// Default is 1 but only for compatibility reasons, it is recommended to set
+// this to 0 because converting wxString to a narrow (non-Unicode) string may
+// fail unless a locale using UTF-8 encoding is used, which is never the case
+// under MSW, for example, hence such conversions can result in silent data
+// loss.
+//
+// Recommended setting: 0
+#define wxUSE_UNSAFE_WXSTRING_CONV 1
+
 // ----------------------------------------------------------------------------
 // debugging settings
 // ----------------------------------------------------------------------------
@@ -1431,9 +1443,9 @@
 // Should wxDC provide SetTransformMatrix() and related methods?
 //
 // Default is 1 but can be set to 0 if this functionality is not used. Notice
-// that currently only wxMSW supports this so setting this to 0 doesn't change
-// much for non-MSW platforms (although it will still save a few bytes
-// probably).
+// that currently wxMSW, wxGTK3 support this for wxDC and all platforms support
+// this for wxGCDC so setting this to 0 doesn't change much if neither of these
+// is used (although it will still save a few bytes probably).
 //
 // Recommended setting: 1.
 #define wxUSE_DC_TRANSFORM_MATRIX 1
diff --git a/setup.h.in b/setup.h.in
index 0e596334db..2093812921 100644
--- a/setup.h.in
+++ b/setup.h.in
@@ -151,6 +151,8 @@
 
 #define wxDIALOG_UNIT_COMPATIBILITY   0
 
+#define wxUSE_UNSAFE_WXSTRING_CONV 0
+
 
 
 #define wxUSE_ON_FATAL_EXCEPTION 0
@@ -545,7 +547,7 @@
 #define wxUSE_DRAG_AND_DROP 0
 
 #ifdef __WXMSW__
-#define wxUSE_ACCESSIBILITY 1
+#define wxUSE_ACCESSIBILITY 0
 #else
 #define wxUSE_ACCESSIBILITY 0
 #endif