diff --git a/ANNOUNCE b/ANNOUNCE
index 40130fb6..a9b2a606 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,60 +1,58 @@
 
-Libpng 1.2.26 - April 2, 2008
+Libpng 1.2.27beta01 - April 12, 2008
 
-This is a public release of libpng, intended for use in production codes.
+This is not intended to be a public release.  It will be replaced
+within a few weeks by a public version or by another test version.
 
 Files available for download:
 
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   libpng-1.2.26.tar.gz
-   libpng-1.2.26.tar.lzma
+   libpng-1.2.27beta01.tar.gz
+   libpng-1.2.27beta01.tar.lzma
      (Get the lzma codec from <http://tukaani.org/lzma>).
-   libpng-1.2.26.tar.bz2
+   libpng-1.2.27beta01.tar.bz2
 
 Source files with LF line endings (for Unix/Linux) without the
 "configure" script
 
-   libpng-1.2.26-no-config.tar.gz
-   libpng-1.2.26-no-config.tar.lzma
-   libpng-1.2.26-no-config.tar.bz2
+   libpng-1.2.27beta01-no-config.tar.gz
+   libpng-1.2.27beta01-no-config.tar.lzma
+   libpng-1.2.27beta01-no-config.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lpng1226.zip
-   lpng1226.7z
-   lpng1226.tar.bz2
+   lp1227b01.zip
+   lp1227b01.7z
+   lp1227b01.tar.bz2
 
 Project files
 
-   libpng-1.2.26-project-netware.zip
-   libpng-1.2.26-project-wince.zip
+   libpng-1.2.27beta01-project-netware.zip
+   libpng-1.2.27beta01-project-wince.zip
 
 Other information:
 
-   libpng-1.2.26-README.txt
-   libpng-1.2.26-KNOWNBUGS.txt
-   libpng-1.2.26-LICENSE.txt
-   libpng-1.2.26-Y2K-compliance.txt
-   libpng-1.2.26-[previous version]-diff.txt
+   libpng-1.2.27beta01-README.txt
+   libpng-1.2.27beta01-KNOWNBUGS.txt
+   libpng-1.2.27beta01-LICENSE.txt
+   libpng-1.2.27beta01-Y2K-compliance.txt
+   libpng-1.2.27beta01-[previous version]-diff.txt
 
-Changes since the last public release (1.2.25):
+Changes since the last public release (1.2.26):
 
-version 1.2.26 [April 2, 2008]
-
-  Added missing "(" in pngmem.c.  Bug introduced in libpng-1.2.2/1.0.13
-  Refined error message returned from deflateInit2 in pngwutil.c
-  Check IHDR length in png_push_read_chunk() before saving it.
-  Revised contrib/gregbook to handle premature end-of-file and file
-    read errors correctly.
-  Free png_ptr->big_row_buf and png_ptr->prev_row before allocating
-    new copies in png_read_start_row().
-  Avoid reallocating big_row_buf and prev_row when the size does not increase.
-  Ifdef out some code that is unused when interlacing is not supported.
+version 1.2.27beta01 [April 12, 2008]
+  Fixed bug (introduced in libpng-1.0.5h) with handling zero-length
+    unknown chunks.
+  Added more information about png_set_keep_unknown_chunks() to the
+    documetation.
+  Reject tRNS chunk with out-of-range samples instead of masking off
+    the invalid high bits as done in since libpng-1.2.19beta5.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+
 (subscription required; visit 
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
 to subscribe) or to glennrp at users.sourceforge.net
diff --git a/CHANGES b/CHANGES
index 52546ac2..ac44681b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2097,9 +2097,20 @@ version 1.2.26beta05 [March 19, 2008]
 version 1.2.26beta06 [March 19, 2008]
   Avoid reallocating big_row_buf and prev_row when the size does not increase.
 
-version 1.2.26rc01 [April 2, 2008]
+version 1.2.26rc01 [March 26, 2008]
   Ifdef out some code that is unused when interlacing is not supported.
 
+versions 1.0.32 and 1.2.26 [April 2, 2008]
+  No changes.
+
+version 1.2.27beta01 [April 12, 2008]
+  Fixed bug (introduced in libpng-1.0.5h) with handling zero-length
+    unknown chunks.
+  Added more information about png_set_keep_unknown_chunks() to the
+    documetation.
+  Reject tRNS chunk with out-of-range samples instead of masking off
+    the invalid high bits as done in since libpng-1.2.19beta5.
+
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
 https://lists.sourceforge.net/lists/listinfo/png-mng-implement
diff --git a/INSTALL b/INSTALL
index ece87578..22c7022f 100644
--- a/INSTALL
+++ b/INSTALL
@@ -1,5 +1,5 @@
 
-Installing libpng version 1.2.26 - April 2, 2008
+Installing libpng version 1.2.27beta01 - April 12, 2008
 
 On Unix/Linux and similar systems, you can simply type
 
@@ -44,7 +44,7 @@ to have access to the zlib.h and zconf.h include files that
 correspond to the version of zlib that's installed.
 
 You can rename the directories that you downloaded (they
-might be called "libpng-1.2.26" or "lpng109" and "zlib-1.2.1"
+might be called "libpng-1.2.27beta01" or "lpng109" and "zlib-1.2.1"
 or "zlib121") so that you have directories called "zlib" and "libpng".
 
 Your directory structure should look like this:
@@ -101,9 +101,9 @@ include
  CMakeLists.txt    =>  "cmake" script
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       gcc, creates libpng12.so.0.1.2.26)
+                       gcc, creates libpng12.so.0.1.2.27beta01)
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng12.so.0.1.2.26)
+                       (gcc, creates libpng12.so.0.1.2.27beta01)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
                        ansi2knr (Requires ansi2knr.c from
@@ -125,14 +125,14 @@ include
  makefile.openbsd  =>  OpenBSD makefile
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng12.so.0.1.2.26)
+                       creates libpng12.so.0.1.2.27beta01)
  makefile.sunos    =>  Sun makefile
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng12.so.0.1.2.26)
+                       creates libpng12.so.0.1.2.27beta01)
  makefile.solaris-x86 =>  Solaris/intelMMX 2.X makefile (gcc,
-                       creates libpng12.so.0.1.2.26)
+                       creates libpng12.so.0.1.2.27beta01)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng12.so.0.1.2.26)
+                       creates libpng12.so.0.1.2.27beta01)
  makefile.32sunu   =>  Sun Ultra 32-bit makefile
  makefile.64sunu   =>  Sun Ultra 64-bit makefile
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/KNOWNBUG b/KNOWNBUG
index d2615dee..1d31ea73 100644
--- a/KNOWNBUG
+++ b/KNOWNBUG
@@ -1,5 +1,5 @@
 
-Known bugs in libpng version 1.2.26
+Known bugs in libpng version 1.2.27beta01
 
 1. February 23, 2006: The custom makefiles don't build libpng with -lz.
 
diff --git a/LICENSE b/LICENSE
index e13d61b6..edc0d4fe 100644
--- a/LICENSE
+++ b/LICENSE
@@ -8,7 +8,7 @@ COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.26, April 2, 2008, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.27beta01, April 12, 2008, are
 Copyright (c) 2004, 2006-2008 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -106,4 +106,4 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 2, 2008
+April 12, 2008
diff --git a/README b/README
index 6b48b245..15b6a282 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng version 1.2.26 - April 2, 2008 (shared library 12.0)
+README for libpng version 1.2.27beta01 - April 12, 2008 (shared library 12.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -191,11 +191,11 @@ Files in this distribution:
        descrip.mms      =>  VMS makefile for MMS or MMK
        makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
        makefile.elf     =>  Linux/ELF makefile symbol versioning,
-                            gcc, creates libpng12.so.0.1.2.26)
+                            gcc, creates libpng12.so.0.1.2.27beta01)
        makefile.linux   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.26)
+                            (gcc, creates libpng12.so.0.1.2.27beta01)
        makefile.gcmmx   =>  Linux/ELF makefile
-                            (gcc, creates libpng12.so.0.1.2.26,
+                            (gcc, creates libpng12.so.0.1.2.27beta01,
                             uses assembler code tuned for Intel MMX platform)
        makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
        makefile.knr     =>  Archaic UNIX Makefile that converts files with
@@ -217,12 +217,12 @@ Files in this distribution:
        makefile.openbsd =>  OpenBSD makefile
        makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
        makefile.sggcc   =>  Silicon Graphics
-                            (gcc, creates libpng12.so.0.1.2.26)
+                            (gcc, creates libpng12.so.0.1.2.27beta01)
        makefile.sunos   =>  Sun makefile
        makefile.solaris =>  Solaris 2.X makefile
-                            (gcc, creates libpng12.so.0.1.2.26)
+                            (gcc, creates libpng12.so.0.1.2.27beta01)
        makefile.so9     =>  Solaris 9 makefile
-                            (gcc, creates libpng12.so.0.1.2.26)
+                            (gcc, creates libpng12.so.0.1.2.27beta01)
        makefile.32sunu  =>  Sun Ultra 32-bit makefile
        makefile.64sunu  =>  Sun Ultra 64-bit makefile
        makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
diff --git a/Y2KINFO b/Y2KINFO
index f6c74926..cb482675 100644
--- a/Y2KINFO
+++ b/Y2KINFO
@@ -1,13 +1,13 @@
    Y2K compliance in libpng:
    =========================
 
-      April 2, 2008
+      April 12, 2008
 
       Since the PNG Development group is an ad-hoc body, we can't make
       an official declaration.
 
       This is your unofficial assurance that libpng from version 0.71 and
-      upward through 1.2.26 are Y2K compliant.  It is my belief that earlier
+      upward through 1.2.27beta01 are Y2K compliant.  It is my belief that earlier
       versions were also Y2K compliant.
 
       Libpng only has three year fields.  One is a 2-byte unsigned integer
diff --git a/configure b/configure
index f18c0ebf..33e8a49d 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.61 for libpng 1.2.26.
+# Generated by GNU Autoconf 2.61 for libpng 1.2.27beta01.
 #
 # Report bugs to <png-mng-implement@lists.sourceforge.net>.
 #
@@ -728,8 +728,8 @@ SHELL=${CONFIG_SHELL-/bin/sh}
 # Identity of this package.
 PACKAGE_NAME='libpng'
 PACKAGE_TARNAME='libpng'
-PACKAGE_VERSION='1.2.26'
-PACKAGE_STRING='libpng 1.2.26'
+PACKAGE_VERSION='1.2.27beta01'
+PACKAGE_STRING='libpng 1.2.27beta01'
 PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
 
 ac_unique_file="pngget.c"
@@ -1406,7 +1406,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures libpng 1.2.26 to adapt to many kinds of systems.
+\`configure' configures libpng 1.2.27beta01 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1476,7 +1476,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpng 1.2.26:";;
+     short | recursive ) echo "Configuration of libpng 1.2.27beta01:";;
    esac
   cat <<\_ACEOF
 
@@ -1586,7 +1586,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpng configure 1.2.26
+libpng configure 1.2.27beta01
 generated by GNU Autoconf 2.61
 
 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
@@ -1600,7 +1600,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpng $as_me 1.2.26, which was
+It was created by libpng $as_me 1.2.27beta01, which was
 generated by GNU Autoconf 2.61.  Invocation command line was
 
   $ $0 $@
@@ -2270,7 +2270,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpng'
- VERSION='1.2.26'
+ VERSION='1.2.27beta01'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -2441,10 +2441,10 @@ fi
 
 
 
-PNGLIB_VERSION=1.2.26
+PNGLIB_VERSION=1.2.27beta01
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=2
-PNGLIB_RELEASE=26
+PNGLIB_RELEASE=27
 
 
 
@@ -21295,7 +21295,7 @@ exec 6>&1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpng $as_me 1.2.26, which was
+This file was extended by libpng $as_me 1.2.27beta01, which was
 generated by GNU Autoconf 2.61.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -21348,7 +21348,7 @@ Report bugs to <bug-autoconf@gnu.org>."
 _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF
 ac_cs_version="\\
-libpng config.status 1.2.26
+libpng config.status 1.2.27beta01
 configured by $0, generated by GNU Autoconf 2.61,
   with options \\"`echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`\\"
 
diff --git a/configure.ac b/configure.ac
index dedbf14e..a0591136 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,15 +18,15 @@ AC_PREREQ(2.59)
 
 dnl Version number stuff here:
 
-AC_INIT([libpng], [1.2.26], [png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng], [1.2.27beta01], [png-mng-implement@lists.sourceforge.net])
 AM_INIT_AUTOMAKE
 dnl stop configure from automagically running automake
 AM_MAINTAINER_MODE
 
-PNGLIB_VERSION=1.2.26
+PNGLIB_VERSION=1.2.27beta01
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=2
-PNGLIB_RELEASE=26
+PNGLIB_RELEASE=27
 
 dnl End of version number stuff
 
diff --git a/libpng-1.2.26.txt b/libpng-1.2.27beta01.txt
similarity index 98%
rename from libpng-1.2.26.txt
rename to libpng-1.2.27beta01.txt
index da1789d5..9be287f1 100644
--- a/libpng-1.2.26.txt
+++ b/libpng-1.2.27beta01.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.26 - April 2, 2008
+ libpng version 1.2.27beta01 - April 12, 2008
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2008 Glenn Randers-Pehrson
@@ -288,6 +288,11 @@ you can retrieve with
 
     png_get_user_chunk_ptr(png_ptr);
 
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks will be saved when read, in case your callback function will need
+one or more of them.  This behavior can be changed with the
+png_set_keep_unknown_chunks() function, described below.
+
 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
 a progress meter or the like.  It's demonstrated in pngtest.c.
@@ -361,6 +366,37 @@ instances of png_set_keep_unknown_chunks(), the final instance will
 take precedence.  The IHDR and IEND chunks should not be named in
 chunk_list; if they are, libpng will process them normally anyway.
 
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)sizeof(unused_chunks)/5);
+    #endif
+
+
 The high-level read interface
 
 At this point there are two ways to proceed; through the high-level
@@ -2796,13 +2832,13 @@ application:
 
 IX. Y2K Compliance in libpng
 
-April 2, 2008
+April 12, 2008
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.2.26 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.27beta01 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
diff --git a/libpng.3 b/libpng.3
index cc954c45..90685e12 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "April 2, 2008"
+.TH LIBPNG 3 "April 12, 2008"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.26
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.27beta01
 .SH SYNOPSIS
 \fB
 #include <png.h>\fP
@@ -410,7 +410,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.2.26 - April 2, 2008
+ libpng version 1.2.27beta01 - April 12, 2008
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2008 Glenn Randers-Pehrson
@@ -698,6 +698,11 @@ you can retrieve with
 
     png_get_user_chunk_ptr(png_ptr);
 
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks will be saved when read, in case your callback function will need
+one or more of them.  This behavior can be changed with the
+png_set_keep_unknown_chunks() function, described below.
+
 At this point, you can set up a callback function that will be
 called after each row has been read, which you can use to control
 a progress meter or the like.  It's demonstrated in pngtest.c.
@@ -771,6 +776,37 @@ instances of png_set_keep_unknown_chunks(), the final instance will
 take precedence.  The IHDR and IEND chunks should not be named in
 chunk_list; if they are, libpng will process them normally anyway.
 
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+    png_byte vpAg[5]={118, 112,  65, 103, (png_byte) '\0'};
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      png_byte unused_chunks[]=
+      {
+        104,  73,  83,  84, (png_byte) '\0',   /* hIST */
+        105,  84,  88, 116, (png_byte) '\0',   /* iTXt */
+        112,  67,  65,  76, (png_byte) '\0',   /* pCAL */
+        115,  67,  65,  76, (png_byte) '\0',   /* sCAL */
+        115,  80,  76,  84, (png_byte) '\0',   /* sPLT */
+        116,  73,  77,  69, (png_byte) '\0',   /* tIME */
+      };
+    #endif
+
+    ...
+
+    #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      /* ignore all unknown chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, NULL, 0);
+      /* except for vpAg: */
+      png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+      /* also ignore unused known chunks: */
+      png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+         (int)sizeof(unused_chunks)/5);
+    #endif
+
+
 .SS The high-level read interface
 
 At this point there are two ways to proceed; through the high-level
@@ -3206,13 +3242,13 @@ application:
 
 .SH IX. Y2K Compliance in libpng
 
-April 2, 2008
+April 12, 2008
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.2.26 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.27beta01 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
@@ -3432,6 +3468,9 @@ the first widely used release:
  1.2.25              13    10225  12.so.0.25[.0]
  1.2.26beta01-06     13    10226  12.so.0.26[.0]
  1.2.26rc01          13    10226  12.so.0.26[.0]
+ 1.2.26              13    10226  12.so.0.26[.0]
+ 1.0.32              10    10032  10.so.0.32[.0]
+ 1.2.27beta01        13    10227  12.so.0.27[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -3487,7 +3526,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.2.26 - April 2, 2008:
+Libpng version 1.2.27beta01 - April 12, 2008:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -3508,7 +3547,7 @@ included in the libpng distribution, the latter shall prevail.)
 If you modify libpng you may insert additional notices immediately following
 this sentence.
 
-libpng versions 1.2.6, August 15, 2004, through 1.2.26, April 2, 2008, are
+libpng versions 1.2.6, August 15, 2004, through 1.2.27beta01, April 12, 2008, are
 Copyright (c) 2004,2006-2008 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -3607,7 +3646,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 2, 2008
+April 12, 2008
 
 .\" end of man page
 
diff --git a/libpngpf.3 b/libpngpf.3
index 8dae69b1..1863f73c 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "April 2, 2008"
+.TH LIBPNGPF 3 "April 12, 2008"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.2.26
+libpng \- Portable Network Graphics (PNG) Reference Library 1.2.27beta01
 (private functions)
 .SH SYNOPSIS
 \fB#include <png.h>\fP
diff --git a/png.5 b/png.5
index b1d697ce..bf92d1d0 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "April 2, 2008"
+.TH PNG 5 "April 12, 2008"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index 2c7de185..bafc0df6 100644
--- a/png.c
+++ b/png.c
@@ -13,7 +13,7 @@
 #include "png.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_26 Your_png_h_is_not_version_1_2_26;
+typedef version_1_2_27beta01 Your_png_h_is_not_version_1_2_27beta01;
 
 /* Version information for C files.  This had better match the version
  * string defined in png.h.  */
@@ -693,7 +693,7 @@ png_charp PNGAPI
 png_get_copyright(png_structp png_ptr)
 {
    png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
-   return ((png_charp) "\n libpng version 1.2.26 - April 2, 2008\n\
+   return ((png_charp) "\n libpng version 1.2.27beta01 - April 12, 2008\n\
    Copyright (c) 1998-2008 Glenn Randers-Pehrson\n\
    Copyright (c) 1996-1997 Andreas Dilger\n\
    Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
diff --git a/png.h b/png.h
index 26907fb0..f01c770e 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.2.26 - April 2, 2008
+ * libpng version 1.2.27beta01 - April 12, 2008
  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -9,7 +9,7 @@
  * Authors and maintainers:
  *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *  libpng versions 0.97, January 1998, through 1.2.26 - April 2, 2008: Glenn
+ *  libpng versions 0.97, January 1998, through 1.2.27beta01 - April 12, 2008: Glenn
  *  See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -181,6 +181,9 @@
  *    1.2.25                  13    10225  12.so.0.25[.0]
  *    1.2.26beta01-06         13    10226  12.so.0.26[.0]
  *    1.2.26rc01              13    10226  12.so.0.26[.0]
+ *    1.2.26                  13    10226  12.so.0.26[.0]
+ *    1.0.32                  10    10032  10.so.0.32[.0]
+ *    1.2.27beta01            13    10227  12.so.0.27[.0]
  *
  *    Henceforth the source version will match the shared-library major
  *    and minor numbers; the shared-library major version number will be
@@ -210,7 +213,7 @@
  * If you modify libpng you may insert additional notices immediately following
  * this sentence.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.2.26, April 2, 2008, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.2.27beta01, April 12, 2008, are
  * Copyright (c) 2004, 2006-2008 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -322,13 +325,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    April 2, 2008
+ *    April 12, 2008
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.2.26 are Y2K compliant.  It is my belief that earlier
+ *    upward through 1.2.27beta01 are Y2K compliant.  It is my belief that earlier
  *    versions were also Y2K compliant.
  *
  *    Libpng only has three year fields.  One is a 2-byte unsigned integer
@@ -384,9 +387,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.2.26"
+#define PNG_LIBPNG_VER_STRING "1.2.27beta01"
 #define PNG_HEADER_VERSION_STRING \
-   " libpng version 1.2.26 - April 2, 2008\n"
+   " libpng version 1.2.27beta01 - April 12, 2008\n"
 
 #define PNG_LIBPNG_VER_SONUM   0
 #define PNG_LIBPNG_VER_DLLNUM  13
@@ -394,11 +397,11 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   2
-#define PNG_LIBPNG_VER_RELEASE 26
+#define PNG_LIBPNG_VER_RELEASE 27
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
 
-#define PNG_LIBPNG_VER_BUILD  0
+#define PNG_LIBPNG_VER_BUILD  01
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -415,14 +418,14 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                        PNG_LIBPNG_BUILD_PRIVATE */
 
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
 
 /* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
  * We must not include leading zeros.
  * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release */
-#define PNG_LIBPNG_VER 10226 /* 1.2.26 */
+#define PNG_LIBPNG_VER 10227 /* 1.2.27 */
 
 #ifndef PNG_VERSION_INFO_ONLY
 /* include the compression library's header */
@@ -1439,7 +1442,7 @@ struct png_struct_def
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef png_structp version_1_2_26;
+typedef png_structp version_1_2_27beta01;
 
 typedef png_struct FAR * FAR * png_structpp;
 
diff --git a/pngconf.h b/pngconf.h
index a65d6532..8fd9d2c9 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.2.26 - April 2, 2008
+ * libpng version 1.2.27beta01 - April 12, 2008
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngpread.c b/pngpread.c
index 9d78deb6..adeb6501 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.2.26 [April 2, 2008]
+ * Last changed in libpng 1.2.27 [April 12, 2008]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1502,9 +1502,14 @@ png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
                  png_sizeof(png_ptr->unknown_chunk.name));
       png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1]='\0';
 
-      png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
       png_ptr->unknown_chunk.size = (png_size_t)length;
-      png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+      if (length == 0)
+         png_ptr->unknown_chunk.data = NULL;
+      else
+      {
+         png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
+         png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+      }
 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
       if(png_ptr->read_user_chunk_fn != NULL)
       {
@@ -1527,8 +1532,11 @@ png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
       else
 #endif
         png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
-      png_free(png_ptr, png_ptr->unknown_chunk.data);
-      png_ptr->unknown_chunk.data = NULL;
+      if (png_ptr->unknown_chunk.data)
+      {
+        png_free(png_ptr, png_ptr->unknown_chunk.data);
+        png_ptr->unknown_chunk.data = NULL;
+      }
    }
    else
 #endif
diff --git a/pngrutil.c b/pngrutil.c
index bd96a0b6..d12b2877 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.2.26 [April 2, 2008]
+ * Last changed in libpng 1.2.27 [April 12, 2008]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -1241,15 +1241,9 @@ void /* PRIVATE */
 png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
    png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
-   int bit_mask;
 
    png_debug(1, "in png_handle_tRNS\n");
 
-   /* For non-indexed color, mask off any bits in the tRNS value that
-    * exceed the bit depth.  Some creators were writing extra bits there.
-    * This is not needed for indexed color. */
-   bit_mask = (1 << png_ptr->bit_depth) - 1;
-
    if (!(png_ptr->mode & PNG_HAVE_IHDR))
       png_error(png_ptr, "Missing IHDR before tRNS");
    else if (png_ptr->mode & PNG_HAVE_IDAT)
@@ -1278,7 +1272,7 @@ png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 
       png_crc_read(png_ptr, buf, 2);
       png_ptr->num_trans = 1;
-      png_ptr->trans_values.gray = png_get_uint_16(buf) & bit_mask;
+      png_ptr->trans_values.gray = png_get_uint_16(buf);
    }
    else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
    {
@@ -1292,9 +1286,9 @@ png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       }
       png_crc_read(png_ptr, buf, (png_size_t)length);
       png_ptr->num_trans = 1;
-      png_ptr->trans_values.red = png_get_uint_16(buf) & bit_mask;
-      png_ptr->trans_values.green = png_get_uint_16(buf + 2) & bit_mask;
-      png_ptr->trans_values.blue = png_get_uint_16(buf + 4) & bit_mask;
+      png_ptr->trans_values.red = png_get_uint_16(buf);
+      png_ptr->trans_values.green = png_get_uint_16(buf + 2);
+      png_ptr->trans_values.blue = png_get_uint_16(buf + 4);
    }
    else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
    {
@@ -2227,9 +2221,14 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
                   (png_charp)png_ptr->chunk_name, 
                   png_sizeof(png_ptr->unknown_chunk.name));
        png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name)-1] = '\0';
-       png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
        png_ptr->unknown_chunk.size = (png_size_t)length;
-       png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+       if (length == 0)
+         png_ptr->unknown_chunk.data = NULL;
+       else
+       {
+         png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
+         png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+       }
 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
        if(png_ptr->read_user_chunk_fn != NULL)
        {
@@ -2252,8 +2251,11 @@ png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
        else
 #endif
          png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
-       png_free(png_ptr, png_ptr->unknown_chunk.data);
-       png_ptr->unknown_chunk.data = NULL;
+       if (png_ptr->unknown_chunk.data)
+       {
+         png_free(png_ptr, png_ptr->unknown_chunk.data);
+         png_ptr->unknown_chunk.data = NULL;
+       }
    }
    else
 #endif
diff --git a/pngset.c b/pngset.c
index 9301dd32..7bc9f850 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,7 +1,7 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * Last changed in libpng 1.2.25 [February 18, 2008]
+ * Last changed in libpng 1.2.27 [April 12, 2008]
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -938,6 +938,18 @@ png_set_tRNS(png_structp png_ptr, png_infop info_ptr,
 
    if (trans_values != NULL)
    {
+      int sample_max = (1 << info_ptr->bit_depth);
+      if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+          (int)trans_values->gray > sample_max) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+          ((int)trans_values->red > sample_max ||
+          (int)trans_values->green > sample_max ||
+          (int)trans_values->blue > sample_max)))
+         {
+            png_warning(png_ptr,
+              "Ignoring tRNS chunk with out-of-range samples for bit_depth");
+            return;
+          }
       png_memcpy(&(info_ptr->trans_values), trans_values,
          png_sizeof(png_color_16));
       if (num_trans == 0)
@@ -1040,28 +1052,31 @@ png_set_unknown_chunks(png_structp png_ptr,
 
     for (i = 0; i < num_unknowns; i++)
     {
-        png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
-        png_unknown_chunkp from = unknowns + i;
+       png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
+       png_unknown_chunkp from = unknowns + i;
 
-        png_memcpy((png_charp)to->name, 
-                   (png_charp)from->name, 
-                   png_sizeof(from->name));
-        to->name[png_sizeof(to->name)-1] = '\0';
+       png_memcpy((png_charp)to->name, 
+                  (png_charp)from->name, 
+                  png_sizeof(from->name));
+       to->name[png_sizeof(to->name)-1] = '\0';
+       to->size = from->size;
+       /* note our location in the read or write sequence */
+       to->location = (png_byte)(png_ptr->mode & 0xff);
 
-        to->data = (png_bytep)png_malloc_warn(png_ptr, from->size);
-        if (to->data == NULL)
-        {
-           png_warning(png_ptr,
+       if (from->size == 0)
+          to->data=NULL;
+       else
+       {
+          to->data = (png_bytep)png_malloc_warn(png_ptr, from->size);
+          if (to->data == NULL)
+          {
+             png_warning(png_ptr,
               "Out of memory while processing unknown chunk.");
-        }
-        else
-        {
-           png_memcpy(to->data, from->data, from->size);
-           to->size = from->size;
-
-           /* note our location in the read or write sequence */
-           to->location = (png_byte)(png_ptr->mode & 0xff);
-        }
+             to->size=0;
+          }
+          else
+             png_memcpy(to->data, from->data, from->size);
+       }
     }
 
     info_ptr->unknown_chunks = np;
diff --git a/pngtest.c b/pngtest.c
index ec7cb2ed..e048532c 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1553,4 +1553,4 @@ main(int argc, char *argv[])
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_26 your_png_h_is_not_version_1_2_26;
+typedef version_1_2_27beta01 your_png_h_is_not_version_1_2_27beta01;
diff --git a/pngwrite.c b/pngwrite.c
index 8b01025f..bc2a4efc 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -112,6 +112,8 @@ png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
             ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
             (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
          {
+            if (up->size == 0)
+               png_warning(png_ptr, "Writing zero-length unknown chunk");
             png_write_chunk(png_ptr, up->name, up->data, up->size);
          }
        }
diff --git a/scripts/CMakeLists.txt b/scripts/CMakeLists.txt
index e718b0c7..f238d839 100644
--- a/scripts/CMakeLists.txt
+++ b/scripts/CMakeLists.txt
@@ -6,7 +6,7 @@ project(PNG)
 
 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 2)
-set(PNGLIB_RELEASE 26)
+set(PNGLIB_RELEASE 27)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
 
@@ -169,7 +169,7 @@ configure_file(${PNG_SOURCE_DIR}/scripts/libpng-config.in
 
 # SET UP LINKS
 set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#    VERSION 0.${PNGLIB_RELEASE}.1.2.26
+#    VERSION 0.${PNGLIB_RELEASE}.1.2.27beta01
      VERSION 0.${PNGLIB_RELEASE}.0
      SOVERSION 0
      CLEAN_DIRECT_OUTPUT 1)
diff --git a/scripts/libpng-config-head.in b/scripts/libpng-config-head.in
index f0d7e93d..53d76d04 100755
--- a/scripts/libpng-config-head.in
+++ b/scripts/libpng-config-head.in
@@ -8,7 +8,7 @@
 
 # Modeled after libxml-config.
 
-version=1.2.26
+version=1.2.27beta01
 prefix=""
 libdir=""
 libs=""
diff --git a/scripts/libpng.pc-configure.in b/scripts/libpng.pc-configure.in
index 7ecb170b..687f3b72 100644
--- a/scripts/libpng.pc-configure.in
+++ b/scripts/libpng.pc-configure.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng12
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.2.26
+Version: 1.2.27beta01
 Libs: -L${libdir} -lpng12
 Cflags: -I${includedir} @LIBPNG_NO_MMX@
diff --git a/scripts/libpng.pc.in b/scripts/libpng.pc.in
index 00c866a7..d38a0734 100644
--- a/scripts/libpng.pc.in
+++ b/scripts/libpng.pc.in
@@ -5,6 +5,6 @@ includedir=@includedir@/libpng12
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.2.26
+Version: 1.2.27beta01
 Libs: -L${libdir} -lpng12
 Cflags: -I${includedir}
diff --git a/scripts/makefile.32sunu b/scripts/makefile.32sunu
index f1de3610..f557915f 100644
--- a/scripts/makefile.32sunu
+++ b/scripts/makefile.32sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.64sunu b/scripts/makefile.64sunu
index 2c4136bf..343de2c5 100644
--- a/scripts/makefile.64sunu
+++ b/scripts/makefile.64sunu
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.aix b/scripts/makefile.aix
index f22e7f26..6a67f32a 100644
--- a/scripts/makefile.aix
+++ b/scripts/makefile.aix
@@ -20,7 +20,7 @@ LN_SF = ln -f -s
 
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 prefix=/usr/local
diff --git a/scripts/makefile.beos b/scripts/makefile.beos
index e33cec15..728ca26a 100644
--- a/scripts/makefile.beos
+++ b/scripts/makefile.beos
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.cygwin b/scripts/makefile.cygwin
index 503995eb..2656a167 100644
--- a/scripts/makefile.cygwin
+++ b/scripts/makefile.cygwin
@@ -74,7 +74,7 @@ CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
 LIBNAME = libpng12
 PNGMAJ = 0
 CYGDLL = 12
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=cygpng$(CYGDLL).dll
diff --git a/scripts/makefile.darwin b/scripts/makefile.darwin
index 62faaee4..d8245df8 100644
--- a/scripts/makefile.darwin
+++ b/scripts/makefile.darwin
@@ -19,7 +19,7 @@ ZLIBINC=../zlib
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.dec b/scripts/makefile.dec
index 6cc6f5d5..c117823f 100644
--- a/scripts/makefile.dec
+++ b/scripts/makefile.dec
@@ -5,7 +5,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.elf b/scripts/makefile.elf
index 331ecd39..c9c750e8 100644
--- a/scripts/makefile.elf
+++ b/scripts/makefile.elf
@@ -12,7 +12,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.gcmmx b/scripts/makefile.gcmmx
index 05132e96..9fc24618 100644
--- a/scripts/makefile.gcmmx
+++ b/scripts/makefile.gcmmx
@@ -14,7 +14,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index 07cbf506..9e674a3f 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -18,7 +18,7 @@ ZLIBINC=/opt/zlib/include
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpgcc b/scripts/makefile.hpgcc
index 3275aad9..53f4996a 100644
--- a/scripts/makefile.hpgcc
+++ b/scripts/makefile.hpgcc
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 2beb9483..8d09ecca 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -18,7 +18,7 @@ ZLIBINC=/opt/zlib/include
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.linux b/scripts/makefile.linux
index 2248460a..403c90f6 100644
--- a/scripts/makefile.linux
+++ b/scripts/makefile.linux
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.mingw b/scripts/makefile.mingw
index 101ba64b..148b237f 100644
--- a/scripts/makefile.mingw
+++ b/scripts/makefile.mingw
@@ -74,7 +74,7 @@ CFLAGS= $(strip $(MINGW_CCFLAGS) $(addprefix -I,$(ZLIBINC)) \
 LIBNAME = libpng12
 PNGMAJ = 0
 MINGDLL = 12
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 SHAREDLIB=libpng$(MINGDLL).dll
diff --git a/scripts/makefile.ne12bsd b/scripts/makefile.ne12bsd
index 816c8f86..07149f3e 100644
--- a/scripts/makefile.ne12bsd
+++ b/scripts/makefile.ne12bsd
@@ -14,7 +14,7 @@ INCSDIR=${LOCALBASE}/include/libpng12
 
 LIB=	png12
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.26
+SHLIB_MINOR=	1.2.27beta01
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.netbsd b/scripts/makefile.netbsd
index f9f712d6..bee275ef 100644
--- a/scripts/makefile.netbsd
+++ b/scripts/makefile.netbsd
@@ -14,7 +14,7 @@ INCSDIR=${LOCALBASE}/include/libpng
 
 LIB=	png
 SHLIB_MAJOR=	3
-SHLIB_MINOR=	1.2.26
+SHLIB_MINOR=	1.2.27beta01
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c
diff --git a/scripts/makefile.nommx b/scripts/makefile.nommx
index 9c0c516d..99705834 100644
--- a/scripts/makefile.nommx
+++ b/scripts/makefile.nommx
@@ -7,7 +7,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.openbsd b/scripts/makefile.openbsd
index dbf295aa..fed4e6be 100644
--- a/scripts/makefile.openbsd
+++ b/scripts/makefile.openbsd
@@ -8,7 +8,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.2.26
+SHLIB_MINOR=	1.2.27beta01
 
 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \
diff --git a/scripts/makefile.sco b/scripts/makefile.sco
index 34ec73ec..7030a385 100644
--- a/scripts/makefile.sco
+++ b/scripts/makefile.sco
@@ -9,7 +9,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sggcc b/scripts/makefile.sggcc
index 7b0bfd40..651f8865 100644
--- a/scripts/makefile.sggcc
+++ b/scripts/makefile.sggcc
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.sgi b/scripts/makefile.sgi
index 154ab65c..753f029b 100644
--- a/scripts/makefile.sgi
+++ b/scripts/makefile.sgi
@@ -6,7 +6,7 @@
 # Library name:
 LIBNAME=libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.so9 b/scripts/makefile.so9
index 66e08a0a..f5a70816 100644
--- a/scripts/makefile.so9
+++ b/scripts/makefile.so9
@@ -8,7 +8,7 @@
 
 # Library name:
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 LIBNAME = libpng12
 
diff --git a/scripts/makefile.solaris b/scripts/makefile.solaris
index 7a3e24d9..a69d8d9a 100644
--- a/scripts/makefile.solaris
+++ b/scripts/makefile.solaris
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/makefile.solaris-x86 b/scripts/makefile.solaris-x86
index 0d31a9a1..24e5dc93 100644
--- a/scripts/makefile.solaris-x86
+++ b/scripts/makefile.solaris-x86
@@ -8,7 +8,7 @@
 # Library name:
 LIBNAME = libpng12
 PNGMAJ = 0
-PNGMIN = 1.2.26
+PNGMIN = 1.2.27beta01
 PNGVER = $(PNGMAJ).$(PNGMIN)
 
 # Shared library names:
diff --git a/scripts/pngos2.def b/scripts/pngos2.def
index 27b3b1e3..db6c5768 100644
--- a/scripts/pngos2.def
+++ b/scripts/pngos2.def
@@ -2,7 +2,7 @@
 ; PNG.LIB module definition file for OS/2
 ;----------------------------------------
 
-; Version 1.2.26
+; Version 1.2.27beta01
 
 LIBRARY		PNG
 DESCRIPTION	"PNG image compression library for OS/2"
diff --git a/scripts/pngw32.def b/scripts/pngw32.def
index c19cb716..a75f8a67 100644
--- a/scripts/pngw32.def
+++ b/scripts/pngw32.def
@@ -5,7 +5,7 @@
 LIBRARY
 
 EXPORTS
-;Version 1.2.26
+;Version 1.2.27beta01
   png_build_grayscale_palette  @1
   png_check_sig        @2
   png_chunk_error      @3