Merge tag 'v1.6.52' into branch 'libpng18' into develop
diff --git a/.appveyor.yml b/.appveyor.yml
index fbea201..52aee12 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,4 +1,4 @@
-version: 1.8.x-{build}
+version: develop-{build}
 
 branches:
   except:
@@ -12,6 +12,8 @@
 
 environment:
   matrix:
+    # FIXME: {TOOLCHAIN: msys2, AUTOMATION: configure, ARCH: i686}
+    # FIXME: {TOOLCHAIN: msys2, AUTOMATION: configure, ARCH: x86_64}
     - TOOLCHAIN: vstudio
       AUTOMATION: cmake
       ARCH: x86
@@ -31,12 +33,6 @@
       AUTOMATION: cmake
       ARCH: x86_64
     - TOOLCHAIN: msys2
-      AUTOMATION: configure
-      ARCH: i686
-    - TOOLCHAIN: msys2
-      AUTOMATION: configure
-      ARCH: x86_64
-    - TOOLCHAIN: msys2
       AUTOMATION: makefiles
       ARCH: i686
     - TOOLCHAIN: msys2
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 65a63b4..5e90024 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -4,11 +4,11 @@
   push:
     branches:
       - libpng16
-      - libpng18
+      - develop
   pull_request:
     branches:
       - libpng16
-      - libpng18
+      - develop
 
 jobs:
   lint:
diff --git a/ANNOUNCE.md b/ANNOUNCE.md
index 94b9ed8..b35915e 100644
--- a/ANNOUNCE.md
+++ b/ANNOUNCE.md
@@ -1,4 +1,4 @@
-libpng 1.8.0.git
+libpng 2.0.0.git
 ================
 
 This is a development version, not intended to be a public release.
diff --git a/CHANGES b/CHANGES
index 26a5427..527dc76 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6315,7 +6315,7 @@
   Added allocation failure fuzzing to oss-fuzz.
     (Contributed by Philippe Antoine.)
 
-Version 1.8.0 [TODO]
+Version 2.0.0 [TODO]
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net.
 Subscription is required; visit
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 004fddb..7b3e52e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,14 +16,14 @@
 
 cmake_minimum_required(VERSION 3.14...4.2)
 
-set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 8)
+set(PNGLIB_MAJOR 2)
+set(PNGLIB_MINOR 0)
 set(PNGLIB_REVISION 0)
 #set(PNGLIB_SUBREVISION 0)
 set(PNGLIB_SUBREVISION "git")
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_REVISION})
-set(PNGLIB_ABI_VERSION ${PNGLIB_MAJOR}${PNGLIB_MINOR})
-set(PNGLIB_SHARED_VERSION ${PNGLIB_ABI_VERSION}.${PNGLIB_REVISION}.${PNGLIB_SUBREVISION})
+set(PNGLIB_ABI_VERSION ${PNGLIB_MAJOR})
+set(PNGLIB_SHARED_VERSION ${PNGLIB_VERSION}.${PNGLIB_SUBREVISION})
 
 project(libpng
         VERSION ${PNGLIB_VERSION}
@@ -813,7 +813,7 @@
           FRAMEWORK DESTINATION "${CMAKE_INSTALL_LIBDIR}")
 
   if(PNG_SHARED)
-    # Create a symlink for libpng.dll.a => libpng18.dll.a on Cygwin
+    # Create a symlink for libpng.dll.a => libpng2.dll.a on Cygwin
     if(NOT WIN32 OR CYGWIN OR MINGW)
       create_symlink(libpng${CMAKE_SHARED_LIBRARY_SUFFIX} TARGET png_shared)
       install(FILES "$<TARGET_LINKER_FILE_DIR:png_shared>/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}"
diff --git a/Makefile.am b/Makefile.am
index fc31e7a..ebf3faa 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -7,7 +7,7 @@
 # For conditions of distribution and use, see the disclaimer
 # and license in png.h
 
-PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@
 
 ACLOCAL_AMFLAGS = -I scripts/autoconf
 
@@ -40,30 +40,30 @@
 
 if ENABLE_TESTS
 pngtest_SOURCES = pngtest.c
-pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngtest_LDADD = libpng@PNGLIB_MAJOR@.la
 
 pngvalid_SOURCES = contrib/libtests/pngvalid.c
-pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngvalid_LDADD = libpng@PNGLIB_MAJOR@.la
 
 pngstest_SOURCES = contrib/libtests/pngstest.c
-pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngstest_LDADD = libpng@PNGLIB_MAJOR@.la
 
 pngunknown_SOURCES = contrib/libtests/pngunknown.c
-pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngunknown_LDADD = libpng@PNGLIB_MAJOR@.la
 
 pngimage_SOURCES = contrib/libtests/pngimage.c
-pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngimage_LDADD = libpng@PNGLIB_MAJOR@.la
 
 timepng_SOURCES = contrib/libtests/timepng.c
-timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+timepng_LDADD = libpng@PNGLIB_MAJOR@.la
 
 pngcp_SOURCES = contrib/tools/pngcp.c
-pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngcp_LDADD = libpng@PNGLIB_MAJOR@.la
 endif
 
 if ENABLE_TOOLS
 pngfix_SOURCES = contrib/tools/pngfix.c
-pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+pngfix_LDADD = libpng@PNGLIB_MAJOR@.la
 
 png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
 endif
@@ -94,37 +94,37 @@
 dist_man_MANS= manuals/libpng.3 manuals/png.5
 
 # generate the -config scripts if required
-binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
-EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
+binconfigs= libpng@PNGLIB_MAJOR@-config
+EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@-config
 bin_SCRIPTS= @binconfigs@
 
 # rules to build libpng, only build the old library on request
-lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
+lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@.la
 # EXTRA_LTLIBRARIES= libpng.la
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
+libpng@PNGLIB_MAJOR@_la_SOURCES = png.c pngerror.c\
 	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
 	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
 	pngsimd.c\
 	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
 
-nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
+nodist_libpng@PNGLIB_MAJOR@_la_SOURCES = pnglibconf.h
 
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
+libpng@PNGLIB_MAJOR@_la_LDFLAGS = -no-undefined -export-dynamic \
 	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
 
 if HAVE_LD_VERSION_SCRIPT
 #   Versioned symbols and restricted exports
 if HAVE_SOLARIS_LD
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
+  libpng@PNGLIB_MAJOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
 else
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
+  libpng@PNGLIB_MAJOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
 endif
 
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
+  libpng@PNGLIB_MAJOR@_la_DEPENDENCIES = libpng.vers
 else
 #   Only restricted exports when possible
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -export-symbols libpng.sym
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
+  libpng@PNGLIB_MAJOR@_la_LDFLAGS += -export-symbols libpng.sym
+  libpng@PNGLIB_MAJOR@_la_DEPENDENCIES = libpng.sym
 endif
 
 #distribute headers in /usr/include/libpng/*
@@ -135,7 +135,7 @@
 # pkg-config stuff, note that libpng.pc is always required in order
 # to get the correct library
 pkgconfigdir = @pkgconfigdir@
-pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
+pkgconfig_DATA = libpng@PNGLIB_MAJOR@.pc
 
 # Extra source distribution files, '${srcdir}' is used below to stop build files
 # from those directories being included.  This only works if the configure is
@@ -149,8 +149,8 @@
 
 SCRIPT_CLEANFILES=scripts/pnglibconf/*.out scripts/pnglibconf/*.chk
 
-CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
-	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
+CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@.pc \
+	libpng@PNGLIB_MAJOR@-config libpng.vers libpng.sym \
 	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
 	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
 	$(SCRIPT_CLEANFILES)
@@ -309,8 +309,8 @@
 	rm pnglibconf.tf6
 	mv pnglibconf.tf7 $@
 
-$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h pnglibconf.h pngpriv.h \
-                                                  pngdebug.h pnginfo.h pngstruct.h pngprefix.h
+$(libpng@PNGLIB_MAJOR@_la_OBJECTS): png.h pngconf.h pnglibconf.h pngpriv.h \
+                                    pngdebug.h pnginfo.h pngstruct.h pngprefix.h
 
 test: check-am
 
diff --git a/README.md b/README.md
index 5e62d97..b56801b 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,4 @@
-README for libpng version 1.8.0.git
+README for libpng version 2.0.0.git
 ===================================
 
 See the note about version numbers near the top of `png.h`.
diff --git a/ci/ci_verify_version.sh b/ci/ci_verify_version.sh
index 5908724..1f586d3 100755
--- a/ci/ci_verify_version.sh
+++ b/ci/ci_verify_version.sh
@@ -62,7 +62,7 @@
     else
         ci_err "mismatched: \$PNG_LIBPNG_VER != $my_expect"
     fi
-    my_expect=$((PNG_LIBPNG_VER_MAJOR*10 + PNG_LIBPNG_VER_MINOR))
+    my_expect=$((PNG_LIBPNG_VER_MAJOR))
     if [[ "$PNG_LIBPNG_VER_SHAREDLIB" == "$my_expect" ]]
     then
         ci_info "matched: \$PNG_LIBPNG_VER_SHAREDLIB == $my_expect"
diff --git a/configure.ac b/configure.ac
index 6b3fa95..90182d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@
 
 dnl Version number stuff here:
 
-AC_INIT([libpng],[1.8.0.git],[png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng],[2.0.0.git],[png-mng-implement@lists.sourceforge.net])
 AC_CONFIG_MACRO_DIR([scripts/autoconf])
 
 # libpng does not follow GNU file name conventions (hence 'foreign')
@@ -42,9 +42,9 @@
 dnl AM_PREREQ([1.11.2])
 dnl stop configure from automagically running automake
 
-PNGLIB_VERSION=1.8.0.git
-PNGLIB_MAJOR=1
-PNGLIB_MINOR=8
+PNGLIB_VERSION=2.0.0.git
+PNGLIB_MAJOR=2
+PNGLIB_MINOR=0
 PNGLIB_RELEASE=0
 
 dnl End of version number stuff
diff --git a/contrib/gregbook/Makefile.sgi b/contrib/gregbook/Makefile.sgi
index 16e0f52..ba32592 100644
--- a/contrib/gregbook/Makefile.sgi
+++ b/contrib/gregbook/Makefile.sgi
@@ -23,9 +23,9 @@
 
 # macros --------------------------------------------------------------------
 
-PNGINC = -I/usr/local/include/libpng18
-PNGLIB = -L/usr/local/lib -lpng18	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng18.a # statically linked against libpng
+PNGINC = -I/usr/local/include/libpng2
+PNGLIB = -L/usr/local/lib -lpng2	# dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng2.a	# statically linked against libpng
 # or:
 #PNGINC = -I../..
 #PNGLIB = -L../.. -lpng
@@ -40,7 +40,7 @@
 
 XINC = -I/usr/include/X11		# old-style, stock X distributions
 XLIB = -L/usr/lib/X11 -lX11
-#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
+#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
 #XLIB = -L/usr/openwin/lib -lX11
 #XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
 #XLIB = -L/usr/X11R6/lib -lX11
diff --git a/contrib/gregbook/Makefile.unx b/contrib/gregbook/Makefile.unx
index c99a8a8..15dc5e3 100644
--- a/contrib/gregbook/Makefile.unx
+++ b/contrib/gregbook/Makefile.unx
@@ -26,14 +26,14 @@
 # macros --------------------------------------------------------------------
 
 #PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng18
-#PNGLIBd = -L$(PNGDIR) -lpng18 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng18.a # statically linked, installed libpng
+#PNGINC = -I/usr/local/include/libpng2
+#PNGLIBd = -L$(PNGDIR) -lpng2 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng2.a # statically linked, installed libpng
 # or:
 PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
 #PNGDIR = ../libpng
 PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng18	# dynamically linked
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng2	# dynamically linked
 PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
 
 ZDIR = /usr/local/lib
diff --git a/libpng-config.in b/libpng-config.in
index 69bf8e3..5df3a4a 100644
--- a/libpng-config.in
+++ b/libpng-config.in
@@ -15,9 +15,9 @@
 prefix="@prefix@"
 exec_prefix="@exec_prefix@"
 libdir="@libdir@"
-includedir="@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
-libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@"
-all_libs="-lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@ @LIBS@"
+includedir="@includedir@/libpng@PNGLIB_MAJOR@"
+libs="-lpng@PNGLIB_MAJOR@"
+all_libs="-lpng@PNGLIB_MAJOR@ @LIBS@"
 I_opts="-I${includedir}"
 L_opts="-L${libdir}"
 R_opts=""
diff --git a/libpng.pc.in b/libpng.pc.in
index de127d4..f4c7250 100644
--- a/libpng.pc.in
+++ b/libpng.pc.in
@@ -1,12 +1,12 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@/libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+includedir=@includedir@/libpng@PNGLIB_MAJOR@
 
 Name: libpng
 Description: Loads and saves PNG files
 Version: @PNGLIB_VERSION@
 Requires.private: zlib
-Libs: -L${libdir} -lpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
+Libs: -L${libdir} -lpng@PNGLIB_MAJOR@
 Libs.private: @LIBS@
 Cflags: -I${includedir}
diff --git a/png.c b/png.c
index 1d7be4d..24b2201 100644
--- a/png.c
+++ b/png.c
@@ -13,7 +13,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_8_0_git Your_png_h_is_not_version_1_8_0_git;
+typedef png_libpng_version_2_0_0_git Your_png_h_is_not_version_2_0_0_git;
 
 /* Sanity check the chunks definitions - PNG_KNOWN_CHUNKS from pngpriv.h and the
  * corresponding macro definitions.  This causes a compile time failure if
@@ -794,7 +794,7 @@
    return PNG_STRING_COPYRIGHT
 #else
    return "\n"
-      "libpng version 1.8.0.git\n"
+      "libpng version 2.0.0.git\n"
       "Copyright (c) 2018-2025 Cosmin Truta\n"
       "Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson\n"
       "Copyright (c) 1996-1997 Andreas Dilger\n"
diff --git a/png.h b/png.h
index 9ab795d..35be19c 100644
--- a/png.h
+++ b/png.h
@@ -1,6 +1,6 @@
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.8.0.git
+ * libpng version 2.0.0.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
@@ -189,18 +189,18 @@
 #define PNG_H
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.8.0.git"
+#define PNG_LIBPNG_VER_STRING "2.0.0.git"
 #define PNG_HEADER_VERSION_STRING " libpng version " PNG_LIBPNG_VER_STRING "\n"
 
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
-#define PNG_LIBPNG_VER_MAJOR   1
-#define PNG_LIBPNG_VER_MINOR   8
+#define PNG_LIBPNG_VER_MAJOR   2
+#define PNG_LIBPNG_VER_MINOR   0
 #define PNG_LIBPNG_VER_RELEASE 0
 
 /* The versions of shared library builds should stay in sync, going forward */
-#define PNG_LIBPNG_VER_SHAREDLIB 18
-#define PNG_LIBPNG_VER_SONUM     PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
-#define PNG_LIBPNG_VER_DLLNUM    PNG_LIBPNG_VER_SHAREDLIB /* [Deprecated] */
+#define PNG_LIBPNG_VER_SHAREDLIB PNG_LIBPNG_VER_MAJOR /* [Deprecated] */
+#define PNG_LIBPNG_VER_SONUM     PNG_LIBPNG_VER_MAJOR /* [Deprecated] */
+#define PNG_LIBPNG_VER_DLLNUM    PNG_LIBPNG_VER_MAJOR /* [Deprecated] */
 
 /* This should be zero for a public release, or non-zero for a
  * development version.
@@ -231,7 +231,7 @@
  * From version 1.0.1 it is:
  * XXYYZZ, where XX=major, YY=minor, ZZ=release
  */
-#define PNG_LIBPNG_VER 10800 /* 1.8.0.git */
+#define PNG_LIBPNG_VER 20000 /* 2.0.0.git */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -341,7 +341,7 @@
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char *png_libpng_version_1_8_0_git;
+typedef char *png_libpng_version_2_0_0_git;
 
 /* Basic control structures: png_struct, png_info, etc.
  *
diff --git a/pngconf.h b/pngconf.h
index c7500f8..357d74a 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,6 +1,6 @@
 /* pngconf.h - machine-configurable file for libpng
  *
- * libpng version 1.8.0.git
+ * libpng version 2.0.0.git
  *
  * Copyright (c) 2018-2025 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
diff --git a/pnglibconf.h.prebuilt b/pnglibconf.h.prebuilt
index 478a693..3761259 100644
--- a/pnglibconf.h.prebuilt
+++ b/pnglibconf.h.prebuilt
@@ -1,6 +1,6 @@
 /* pnglibconf.h - library build configuration */
 
-/* libpng version 1.8.0.git */
+/* libpng version 2.0.0.git */
 
 /* Copyright (c) 2018-2025 Cosmin Truta */
 /* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
diff --git a/pngtest.c b/pngtest.c
index 2caade4..5582499 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -51,16 +51,12 @@
 #define STDERR stdout
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_8_0_git Your_png_h_is_not_version_1_8_0_git;
+typedef png_libpng_version_2_0_0_git Your_png_h_is_not_version_2_0_0_git;
 
 /* Ensure that all version numbers in png.h are consistent with one another. */
 #if (PNG_LIBPNG_VER != PNG_LIBPNG_VER_MAJOR * 10000 + \
                        PNG_LIBPNG_VER_MINOR * 100 + \
-                       PNG_LIBPNG_VER_RELEASE) || \
-    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_MAJOR * 10 + \
-                                 PNG_LIBPNG_VER_MINOR) || \
-    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_SONUM) || \
-    (PNG_LIBPNG_VER_SHAREDLIB != PNG_LIBPNG_VER_DLLNUM)
+                       PNG_LIBPNG_VER_RELEASE)
 #  error Inconsistent version numbers in "png.h"
 #endif
 
diff --git a/projects/vstudio/README.txt b/projects/vstudio/README.txt
index a32dead..fdc0e1c 100644
--- a/projects/vstudio/README.txt
+++ b/projects/vstudio/README.txt
@@ -40,7 +40,7 @@
 
 If you don't use the Visual Studio defaults your application must still
 be built with the default runtime option (/MD).  If, for some reason,
-it is not then your application will crash inside libpng18.dll as soon
+it is not then your application will crash inside libpng2.dll as soon
 as libpng tries to read from a file handle you pass in.
 
 If you do not want to use the DLL, and prefer static linking instead,
diff --git a/projects/vstudio/pngstest/pngstest.vcxproj b/projects/vstudio/pngstest/pngstest.vcxproj
index 0931e5f..5a3fd8e 100644
--- a/projects/vstudio/pngstest/pngstest.vcxproj
+++ b/projects/vstudio/pngstest/pngstest.vcxproj
@@ -164,7 +164,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -197,7 +197,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -230,7 +230,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -263,7 +263,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -297,7 +297,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -332,7 +332,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -368,7 +368,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -404,7 +404,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
diff --git a/projects/vstudio/pngtest/pngtest.vcxproj b/projects/vstudio/pngtest/pngtest.vcxproj
index 9a9e850..52340af 100644
--- a/projects/vstudio/pngtest/pngtest.vcxproj
+++ b/projects/vstudio/pngtest/pngtest.vcxproj
@@ -164,7 +164,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -197,7 +197,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -230,7 +230,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -263,7 +263,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -298,7 +298,7 @@
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -333,7 +333,7 @@
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -368,7 +368,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
@@ -405,7 +405,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
diff --git a/projects/vstudio/pngunknown/pngunknown.vcxproj b/projects/vstudio/pngunknown/pngunknown.vcxproj
index ebcd081..2ff2249 100644
--- a/projects/vstudio/pngunknown/pngunknown.vcxproj
+++ b/projects/vstudio/pngunknown/pngunknown.vcxproj
@@ -164,7 +164,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -197,7 +197,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -230,7 +230,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -263,7 +263,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -297,7 +297,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -332,7 +332,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -368,7 +368,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -404,7 +404,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
diff --git a/projects/vstudio/pngvalid/pngvalid.vcxproj b/projects/vstudio/pngvalid/pngvalid.vcxproj
index 32caae3..4c53c1f 100644
--- a/projects/vstudio/pngvalid/pngvalid.vcxproj
+++ b/projects/vstudio/pngvalid/pngvalid.vcxproj
@@ -164,7 +164,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -197,7 +197,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -230,7 +230,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -263,7 +263,7 @@
     <Link>
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
     </Link>
     <CustomBuildStep>
@@ -297,7 +297,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -332,7 +332,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -368,7 +368,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
@@ -404,7 +404,7 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>libpng18.lib;zlib.lib</AdditionalDependencies>
+      <AdditionalDependencies>libpng2.lib;zlib.lib</AdditionalDependencies>
       <AdditionalLibraryDirectories>$(OutDir)</AdditionalLibraryDirectories>
       <LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
     </Link>
diff --git a/scripts/libpng-config-head.in b/scripts/libpng-config-head.in
index 2eb2924..d6fe8a7 100644
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -11,7 +11,7 @@
 
 # Modeled after libxml-config.
 
-version=1.8.0.git
+version=2.0.0.git
 prefix=""
 libdir=""
 libs=""
diff --git a/scripts/libpng.pc.in b/scripts/libpng.pc.in
index c36a09e..63cbcd4 100644
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -1,10 +1,10 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
 libdir=@libdir@
-includedir=@includedir@/libpng18
+includedir=@includedir@/libpng2
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.8.0.git
-Libs: -L${libdir} -lpng18
+Version: 2.0.0.git
+Libs: -L${libdir} -lpng2
 Cflags: -I${includedir}