diff --git a/ANNOUNCE b/ANNOUNCE
index c5021fd48..60f3cf115 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.7.0alpha01 - December 10, 2012
+Libpng 1.7.0alpha01 - December 15, 2012
 
 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.
@@ -26,7 +26,7 @@ Other information:
 
 Changes since the last public release (1.6.0):
 
-Version 1.7.0alpha01 [December 10, 2012]
+Version 1.7.0alpha01 [December 15, 2012]
   Started 1.7.0 branch from libpng-1.6.0beta33.
   Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
     changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
@@ -45,6 +45,14 @@ Version 1.7.0alpha01 [December 10, 2012]
     more calculations and the algorithm used to minimize the number of
     calculations has been extended to all the 16-bit tables; it has advantages
     for any significant gamma correction.
+  Rearranged png_struct, remove unused members, change png_set_filter handling
+    png_struct members rearranged - partly to reorder to avoid packing, partly
+    to put frequently accessed members at the start and partly to make
+    the grouping more clear. png_set_filter code has been rewritten and the
+    code shared with png_write_start_row moved to a common function.  Comments
+    in png.h have been made more clear. Minor fixes to
+    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
+    more error detection in png_set_tRNS.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index e1d2dfcc3..c35450007 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4311,7 +4311,7 @@ Version 1.6.0beta33 [December 10, 2012]
     fall-through condition.
   Change png_warning() to png_app_warning() in png_write_tRNS().
 
-Version 1.7.0alpha01 [December 10, 2012]
+Version 1.7.0alpha01 [December 15, 2012]
   Started 1.7.0 branch from libpng-1.6.0beta33.
   Made 8-bit compose and rgb_to_grayscale accuracy improvements.  These
     changes cause 16-bit arithmetic to be used for 8-bit data in the gamma
@@ -4330,6 +4330,14 @@ Version 1.7.0alpha01 [December 10, 2012]
     more calculations and the algorithm used to minimize the number of
     calculations has been extended to all the 16-bit tables; it has advantages
     for any significant gamma correction.
+  Rearranged png_struct, remove unused members, change png_set_filter handling
+    png_struct members rearranged - partly to reorder to avoid packing, partly
+    to put frequently accessed members at the start and partly to make
+    the grouping more clear. png_set_filter code has been rewritten and the
+    code shared with png_write_start_row moved to a common function.  Comments
+    in png.h have been made more clear. Minor fixes to
+    contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
+    more error detection in png_set_tRNS.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/contrib/libtests/timepng.c b/contrib/libtests/timepng.c
index 4d5780428..51ff98376 100644
--- a/contrib/libtests/timepng.c
+++ b/contrib/libtests/timepng.c
@@ -252,7 +252,7 @@ int main(int argc, char **argv)
 
          while (fgets(filename, FILENAME_MAX+1, stdin))
          {
-            int len = strlen(filename);
+            size_t len = strlen(filename);
 
             if (filename[len-1] == '\n')
             {
diff --git a/png.c b/png.c
index 83c5c0380..7dbd60c28 100644
--- a/png.c
+++ b/png.c
@@ -14,7 +14,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0alpha01 Your_png_h_is_not_version_1_7_0alpha01;
+typedef png_libpng_version_1_6_0beta32 Your_png_h_is_not_version_1_6_0beta32;
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
@@ -744,13 +744,13 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.7.0alpha01 - December 10, 2012" PNG_STRING_NEWLINE \
+     "libpng version 1.6.0beta32 - November 25, 2012" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2012 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 1.7.0alpha01 - December 10, 2012\
+      return "libpng version 1.6.0beta32 - November 25, 2012\
       Copyright (c) 1998-2012 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 77619edbe..9b2d940e1 100644
--- a/png.h
+++ b/png.h
@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.7.0alpha01 - December 10, 2012
+ * libpng version 1.6.0beta32 - November 25, 2012
  * Copyright (c) 1998-2012 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 1.7.0alpha01 - December 10, 2012: Glenn
+ *   libpng versions 0.97, January 1998, through 1.6.0beta32 - November 25, 2012: Glenn
  *   See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -198,7 +198,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.7.0alpha01, December 10, 2012, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.0beta32, November 25, 2012, 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:
@@ -310,13 +310,13 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    December 10, 2012
+ *    November 25, 2012
  *
  *    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 1.7.0alpha01 are Y2K compliant.  It is my belief that
+ *    upward through 1.6.0beta32 are Y2K compliant.  It is my belief that
  *    earlier versions were also Y2K compliant.
  *
  *    Libpng only has two year fields.  One is a 2-byte unsigned integer
@@ -376,23 +376,23 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.7.0alpha01"
+#define PNG_LIBPNG_VER_STRING "1.6.0beta32"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.7.0alpha01 - December 10, 2012\n"
+     " libpng version 1.6.0beta32 - November 25, 2012\n"
 
-#define PNG_LIBPNG_VER_SONUM   17
-#define PNG_LIBPNG_VER_DLLNUM  17
+#define PNG_LIBPNG_VER_SONUM   16
+#define PNG_LIBPNG_VER_DLLNUM  16
 
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
-#define PNG_LIBPNG_VER_MINOR   7
+#define PNG_LIBPNG_VER_MINOR   6
 #define PNG_LIBPNG_VER_RELEASE 0
 
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
  */
 
-#define PNG_LIBPNG_VER_BUILD  01
+#define PNG_LIBPNG_VER_BUILD  32
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -409,7 +409,7 @@
 #define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                        PNG_LIBPNG_BUILD_PRIVATE */
 
-#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_ALPHA
+#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.
@@ -417,7 +417,7 @@
  * 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 10700 /* 1.7.0 */
+#define PNG_LIBPNG_VER 10600 /* 1.6.0 */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -522,7 +522,7 @@ extern "C" {
 /* 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_7_0alpha01;
+typedef char* png_libpng_version_1_6_0beta32;
 
 /* Basic control structions.  Read libpng-manual.txt or libpng.3 for more info.
  *
diff --git a/pngconf.h b/pngconf.h
index eb2acb114..b17989cb0 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.7.0alpha01 - December 10, 2012
+ * libpng version 1.6.0beta32 - November 25, 2012
  *
  * Copyright (c) 1998-2012 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
diff --git a/pngerror.c b/pngerror.c
index a52844a41..a97778b3c 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -163,7 +163,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
          case PNG_NUMBER_FORMAT_02u:
             /* Expects at least 2 digits. */
             mincount = 2;
-            /* FALL THROUGH */
+            /* fall through */
 
          case PNG_NUMBER_FORMAT_u:
             *--end = digits[number % 10];
@@ -173,7 +173,7 @@ png_format_number(png_const_charp start, png_charp end, int format,
          case PNG_NUMBER_FORMAT_02x:
             /* This format expects at least two digits */
             mincount = 2;
-            /* FALL THROUGH */
+            /* fall through */
 
          case PNG_NUMBER_FORMAT_x:
             *--end = digits[number & 0xf];
diff --git a/pngrtran.c b/pngrtran.c
index 9d77457dd..602d98aea 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1009,7 +1009,9 @@ png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
 
          png_ptr->rgb_to_gray_red_coeff   = red_int;
          png_ptr->rgb_to_gray_green_coeff = green_int;
-         png_ptr->rgb_to_gray_coefficients_set = 1;
+#        if defined PNG_COLORS_SPACE_SUPPORTED || defined PNG_GAMMA_SUPPORTED
+            png_ptr->colorspace.flags |= PNG_COLORSPACE_RGB_TO_GRAY_SET;
+#        endif
       }
 
       else
diff --git a/pngtest.c b/pngtest.c
index 21a8c5745..3859a6d62 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1949,4 +1949,4 @@ main(void)
 #endif
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_7_0alpha01 Your_png_h_is_not_version_1_7_0alpha01;
+typedef png_libpng_version_1_6_0beta32 Your_png_h_is_not_version_1_6_0beta32;
diff --git a/pngwutil.c b/pngwutil.c
index c7d9e7217..68d572962 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1446,6 +1446,7 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
       /* One 16 bit value */
       if (tran->gray >= (1 << png_ptr->bit_depth))
       {
+         /* This can no longer happen because it is checked in png_set_tRNS */
          png_warning(png_ptr,
              "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
 
@@ -1468,7 +1469,8 @@ png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
       if (buf[0] | buf[2] | buf[4])
 #endif
       {
-         png_app_warning(png_ptr,
+         /* Also checked in png_set_tRNS */
+         png_warning(png_ptr,
            "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
          return;
       }
@@ -1521,7 +1523,6 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
       if (buf[0] | buf[2] | buf[4])
 #endif
       {
-         /* This can no longer happen because it is checked in png_set_tRNS */
          png_warning(png_ptr,
              "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
 
@@ -1535,7 +1536,6 @@ png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
    {
       if (back->gray >= (1 << png_ptr->bit_depth))
       {
-         /* Also checked in png_set_tRNS */
          png_warning(png_ptr,
              "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
 
diff --git a/scripts/pnglibconf.dfa b/scripts/pnglibconf.dfa
index b66ca80e1..4cc620ec9 100644
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -286,9 +286,9 @@ option IO_STATE
 # read:
 
 # Added at libpng-1.2.43; adds limit fields to png_struct,
-# allows some usages of these fields
+# allows some usages of these fields, from 1.7.0 only limits read
 
-option USER_LIMITS
+option USER_LIMITS requires READ
 
 # Added at libpng-1.2.6; adds setting APIs, allows additional
 # usage of this field (UTSL)