diff --git a/ANNOUNCE b/ANNOUNCE
index c7f51fbb7..038f7ea4a 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -58,6 +58,12 @@ Version 1.6.3beta05 [May 8, 2013]
   Added fixitxt and pngdeflate to the built programs and removed warnings
     from the source code and timepng that are revealed as a result.  Fixed
     fixitxt when the chunk length is more than 65535 (untested, no test case).
+  Detect wrong libpng versions linked to pngdeflate, which currently
+    only works with libpng versions that can be made to reliably fail when
+    the deflate data contains an out-of-window reference.  This means only
+    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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diff --git a/CHANGES b/CHANGES
index ff162a319..a02553d24 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4541,6 +4541,12 @@ Version 1.6.3beta05 [May 8, 2013]
   Added fixitxt and pngdeflate to the built programs and removed warnings
     from the source code and timepng that are revealed as a result.  Fixed
     fixitxt when the chunk length is more than 65535 (untested, no test case).
+  Detect wrong libpng versions linked to pngdeflate, which currently
+    only works with libpng versions that can be made to reliably fail when
+    the deflate data contains an out-of-window reference.  This means only
+    1.6 and later.
+  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+    message which it is easier to work round than ignore.
 
 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 523627f38..7c937971c 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/contrib/tools/pngdeflate.c b/contrib/tools/pngdeflate.c
index 087cab79e..39562b3e1 100644
--- a/contrib/tools/pngdeflate.c
+++ b/contrib/tools/pngdeflate.c
@@ -13,13 +13,47 @@
  */
 #include <stdlib.h>
 #include <stdio.h>
-#ifdef PNG_READ_SUPPORTED
 #include <string.h>
 #include <ctype.h>
 
-#include <png.h>
+/* Define the following to use this program against your installed libpng,
+ * rather than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+
+#if PNG_LIBPNG_VER < 10600 /* 1.6.0 */
+#  error pngdeflate will not work with libpng versions prior to 1.6
+#endif
+
+#ifdef PNG_READ_SUPPORTED
 #include <zlib.h>
 
+#ifndef PNG_MAXIMUM_INFLATE_WINDOW
+#  if PNG_LIBPNG_VER != 10600 && PNG_LIBPNG_VER != 10601 && \
+      PNG_LIBPNG_VER != 10602
+#     error pngdeflate not supported in this libpng version
+#  endif
+#endif
+
+/* Copied from pngpriv.h */
+#ifdef __cplusplus
+#  define png_voidcast(type, value) static_cast<type>(value)
+#  define png_constcast(type, value) const_cast<type>(value)
+#  define png_aligncast(type, value) \
+   static_cast<type>(static_cast<void*>(value))
+#  define png_aligncastconst(type, value) \
+   static_cast<type>(static_cast<const void*>(value))
+#else
+#  define png_voidcast(type, value) (value)
+#  define png_constcast(type, value) ((type)(value))
+#  define png_aligncast(type, value) ((void*)(value))
+#  define png_aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
 static int idat_error = 0;
 static int verbose = 0;
 static int errors = 0;
@@ -204,8 +238,8 @@ read_png(FILE *fp)
    {
       png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
-      row = malloc(rowbytes);
-      display = malloc(rowbytes);
+      row = png_voidcast(png_byte*, malloc(rowbytes));
+      display = png_voidcast(png_byte*, malloc(rowbytes));
 
       if (row == NULL || display == NULL)
          png_error(png_ptr, "OOM allocating row buffers");
@@ -524,11 +558,10 @@ fix_one(FILE *fp, FILE *fpIn, IDAT_info *info, png_uint_32 max_IDAT, int strip)
          {
             rx(fpIn, info->header + state, 1);
             wx(fp, info->header + state, 1);
-            ++state;
             ++len_IDAT;
             --len;
 
-            if (state == 2)
+            if (state++ == 1)
             {
                /* The zlib stream is used to validate the compressed IDAT
                 * data in the most relaxed way possible.
diff --git a/pngrutil.c b/pngrutil.c
index ba50d6ecb..34687a0f2 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.6.2 [April 25, 2013]
+ * Last changed in libpng 1.6.3 [(PENDING RELEASE)]
  * 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.)