diff --git a/ANNOUNCE b/ANNOUNCE
index 7facdec..eb457bb 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.5.16beta04 - April 26, 2013
+Libpng 1.5.16beta04 - May 1, 2013
 
 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.
@@ -42,7 +42,9 @@
 Version 1.5.16beta03 [April 26, 2013]
   Test for 'arm*' not just 'arm' in the host_cpu configure variable.
 
-Version 1.5.16beta04 [April 26, 2013]
+Version 1.5.16beta04 [May 1, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index a131905..cdbdc8d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4086,7 +4086,9 @@
 Version 1.5.16beta03 [April 26, 2013]
   Test for 'arm*' not just 'arm' in the host_cpu configure variable.
 
-Version 1.5.16beta04 [April 26, 2013]
+Version 1.5.16beta04 [May 1, 2013]
+  Expanded manual paragraph about writing private chunks, particularly
+    the need to call png_set_keep_unknown_chunks() when writing them.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/LICENSE b/LICENSE
index 81b52a9..a2c01be 100644
--- a/LICENSE
+++ b/LICENSE
@@ -10,7 +10,7 @@
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, April 26, 2013, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, May 1, 2013, are
 Copyright (c) 2004, 2006-2012 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
@@ -108,4 +108,4 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 26, 2013
+May 1, 2013
diff --git a/README b/README
index 1a6380c..cb924bf 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-README for libpng version 1.5.16beta04 - April 26, 2013 (shared library 15.0)
+README for libpng version 1.5.16beta04 - May 1, 2013 (shared library 15.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
diff --git a/libpng-manual.txt b/libpng-manual.txt
index c672b5b..4c465aa 100644
--- a/libpng-manual.txt
+++ b/libpng-manual.txt
@@ -1,6 +1,6 @@
 Libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.5.16beta04 - April 29, 2013
+ libpng version 1.5.16beta04 - May 1, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.5.16beta04 - April 29, 2013
+ libpng versions 0.97, January 1998, through 1.5.16beta04 - May 1, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -4655,7 +4655,7 @@
 
 XIV. Y2K Compliance in libpng
 
-April 29, 2013
+May 1, 2013
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
diff --git a/libpng.3 b/libpng.3
index edec271..e42cf1c 100644
--- a/libpng.3
+++ b/libpng.3
@@ -1,4 +1,4 @@
-.TH LIBPNG 3 "April 29, 2013"
+.TH LIBPNG 3 "May 1, 2013"
 .SH NAME
 libpng \- Portable Network Graphics (PNG) Reference Library 1.5.16beta04
 .SH SYNOPSIS
@@ -492,7 +492,7 @@
 .SH LIBPNG.TXT
 Libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.5.16beta04 - April 29, 2013
+ libpng version 1.5.16beta04 - May 1, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -503,7 +503,7 @@
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.5.16beta04 - April 29, 2013
+ libpng versions 0.97, January 1998, through 1.5.16beta04 - May 1, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -5148,7 +5148,7 @@
 
 .SH XIV. Y2K Compliance in libpng
 
-April 29, 2013
+May 1, 2013
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
@@ -5437,7 +5437,7 @@
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.5.16beta04 - April 29, 2013:
+Libpng version 1.5.16beta04 - May 1, 2013:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -5460,7 +5460,7 @@
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, April 29, 2013, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, May 1, 2013, are
 Copyright (c) 2004,2006-2007 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
@@ -5559,7 +5559,7 @@
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 29, 2013
+May 1, 2013
 
 .\" end of man page
 
diff --git a/libpngpf.3 b/libpngpf.3
index 93c3d4a..382b73f 100644
--- a/libpngpf.3
+++ b/libpngpf.3
@@ -1,4 +1,4 @@
-.TH LIBPNGPF 3 "April 26, 2013"
+.TH LIBPNGPF 3 "May 1, 2013"
 .SH NAME
 libpng \- Portable Network Graphics (PNG) Reference Library 1.5.16beta04
 (private functions)
diff --git a/png.5 b/png.5
index cde3820..57b58a0 100644
--- a/png.5
+++ b/png.5
@@ -1,4 +1,4 @@
-.TH PNG 5 "April 26, 2013"
+.TH PNG 5 "May 1, 2013"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION
diff --git a/png.c b/png.c
index 68f8c73..450c2c7 100644
--- a/png.c
+++ b/png.c
@@ -658,13 +658,13 @@
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.5.16beta04 - April 26, 2013" PNG_STRING_NEWLINE \
+     "libpng version 1.5.16beta04 - May 1, 2013" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2013 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.5.16beta04 - April 26, 2013\
+      return "libpng version 1.5.16beta04 - May 1, 2013\
       Copyright (c) 1998-2013 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
diff --git a/png.h b/png.h
index 0c1ac18..b06b2e9 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.5.16beta04 - April 26, 2013
+ * libpng version 1.5.16beta04 - May 1, 2013
  * Copyright (c) 1998-2013 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.)
@@ -11,7 +11,7 @@
  * 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 1.5.16beta04 - April 26, 2013: Glenn
+ *   libpng versions 0.97, January 1998, through 1.5.16beta04 - May 1, 2013: Glenn
  *   See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -219,7 +219,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, April 26, 2013, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.5.16beta04, May 1, 2013, are
  * Copyright (c) 2004, 2006-2013 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:
@@ -331,7 +331,7 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    April 26, 2013
+ *    May 1, 2013
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
@@ -398,7 +398,7 @@
 /* Version information for png.h - this should match the version in png.c */
 #define PNG_LIBPNG_VER_STRING "1.5.16beta04"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.5.16beta04 - April 26, 2013\n"
+     " libpng version 1.5.16beta04 - May 1, 2013\n"
 
 #define PNG_LIBPNG_VER_SONUM   15
 #define PNG_LIBPNG_VER_DLLNUM  15
diff --git a/pngconf.h b/pngconf.h
index f5e214d..6c409d8 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.5.16beta04 - April 26, 2013
+ * libpng version 1.5.16beta04 - May 1, 2013
  *
  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngrutil.c b/pngrutil.c
index 649ecc2..844c6d8 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -18,8 +18,6 @@
 
 #ifdef PNG_READ_SUPPORTED
 
-#define png_strtod(p,a,b) strtod(a,b)
-
 png_uint_32 PNGAPI
 png_get_uint_31(png_structp png_ptr, png_const_bytep buf)
 {
diff --git a/projects/vstudio/readme.txt b/projects/vstudio/readme.txt
index 146ddec..ccfae0a 100644
--- a/projects/vstudio/readme.txt
+++ b/projects/vstudio/readme.txt
@@ -1,7 +1,7 @@
 
 VisualStudio instructions
 
-libpng version 1.5.16beta04 - April 26, 2013
+libpng version 1.5.16beta04 - May 1, 2013
 
 Copyright (c) 1998-2010 Glenn Randers-Pehrson
 
diff --git a/projects/vstudio/zlib.props b/projects/vstudio/zlib.props
index 269cc50..e5adb12 100644
--- a/projects/vstudio/zlib.props
+++ b/projects/vstudio/zlib.props
@@ -2,7 +2,7 @@
 <!--
  * zlib.props - location of zlib source
  *
- * libpng version 1.5.16beta04 - April 26, 2013
+ * libpng version 1.5.16beta04 - May 1, 2013
  *
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  *
diff --git a/scripts/README.txt b/scripts/README.txt
index ab57893..2893a61 100644
--- a/scripts/README.txt
+++ b/scripts/README.txt
@@ -1,5 +1,5 @@
 
-Makefiles for  libpng version 1.5.16beta04 - April 26, 2013
+Makefiles for  libpng version 1.5.16beta04 - May 1, 2013
 
 pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.linux    =>  Linux/ELF makefile
diff --git a/scripts/pnglibconf.h.prebuilt b/scripts/pnglibconf.h.prebuilt
index 1dab6b5..e5765be 100644
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -1,7 +1,7 @@
 /* 1.5.16beta04 STANDARD API DEFINITION */
 /* pnglibconf.h - library build configuration */
 
-/* libpng version 1.5.16beta04 - April 26, 2013 */
+/* libpng version 1.5.16beta04 - May 1, 2013 */
 
 /* Copyright (c) 1998-2013 Glenn Randers-Pehrson */