diff --git a/ANNOUNCE b/ANNOUNCE
index 806ead9..b68c8db 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.4.6beta06 - March 14, 2011
+Libpng 1.4.6beta06 - January 23, 2011
 
 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.
@@ -49,9 +49,7 @@
   Fixed a typo in the *.def files and deleted entries that are now
     declared in pngpriv.h
 
-version 1.4.6beta06 [March 14, 2011]
-  Updated contrib/pngsuite/README to add the word "modify".
-  Added the private PNG_UNUSED() macro definition in pngconf.h.
+version 1.4.6beta06 [January 23, 2011]
 
 Send comments/corrections/commendations to glennrp at users.sourceforge.net
 or to png-mng-implement at lists.sf.net (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 854e32c..34bb1c2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2761,9 +2761,7 @@
   Fixed a typo in the *.def files and deleted entries that are now
     declared in pngpriv.h
 
-version 1.4.6beta06 [March 14, 2011]
-  Updated contrib/pngsuite/README to add the word "modify".
-  Added the private PNG_UNUSED() macro definition in pngconf.h.
+version 1.4.6beta06 [January 23, 2011]
 
 Send comments/corrections/commendations to glennrp at users.sourceforge.net
 or to png-mng-implement at lists.sf.net (subscription required; visit
diff --git a/contrib/pngsuite/README b/contrib/pngsuite/README
index 714baff..714d12c 100644
--- a/contrib/pngsuite/README
+++ b/contrib/pngsuite/README
@@ -1,58 +1,41 @@
 
 pngsuite
 --------
-(c) Willem van Schaik, 1999, 2011
+(c) Willem van Schaik, 1999
 
-Permission to use, copy, modify, and distribute these images for any
-purpose and without fee is hereby granted.
+Permission to use, copy, and distribute these images for any purpose and
+without fee is hereby granted.
 
-The 15 "bas*.png" images are part of the much larger PngSuite test-set of 
+These 15 images are part of the much larger PngSuite test-set of 
 images, available for developers of PNG supporting software. The 
 complete set, available at http:/www.schaik.com/pngsuite/, contains 
 a variety of images to test interlacing, gamma settings, ancillary
 chunks, etc.
 
-The "ft*.png" images are "free/libre" replacements for the transparent
-corresponding t*.png images in the PngSuite.
-
 The images in this directory represent the basic PNG color-types:
 grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
 (1-8 bit) and grayscale or color images with alpha channel. You
 can use them to test the proper functioning of PNG software.
 
-    filename       depth type
+    filename      depth type
     ------------ ------ --------------
-    basn0g01.png   1-bit grayscale
-    basn0g02.png   2-bit grayscale
-    basn0g04.png   4-bit grayscale
-    basn0g08.png   8-bit grayscale
-    basn0g16.png  16-bit grayscale
-    basn2c08.png   8-bit truecolor
-    basn2c16.png  16-bit truecolor
-    basn3p01.png   1-bit paletted
-    basn3p02.png   2-bit paletted
-    basn3p04.png   4-bit paletted
-    basn3p08.png   8-bit paletted
-    basn4a08.png   8-bit gray with alpha
-    basn4a16.png  16-bit gray with alpha
-    basn6a08.png   8-bit RGBA
-    basn6a16.png  16-bit RGBA
+    basn0g01.png  1-bit grayscale
+    basn0g02.png  2-bit grayscale
+    basn0g04.png  4-bit grayscale
+    basn0g08.png  8-bit grayscale
+    basn0g16.png 16-bit grayscale
+    basn2c08.png  8-bit truecolor
+    basn2c16.png 16-bit truecolor
+    basn3p01.png  1-bit paletted
+    basn3p02.png  2-bit paletted
+    basn3p04.png  4-bit paletted
+    basn3p08.png  8-bit paletted
+    basn4a08.png  8-bit gray with alpha
+    basn4a16.png 16-bit gray with alpha
+    basn6a08.png  8-bit RGBA
+    basn6a16.png 16-bit RGBA
 
-    ftbbn0g04.png  4-bit grayscale, black bKGD
-    ftbbn2c16.png 16-bit truecolor, black bKGD
-    ftbbn3p08.png  8-bit paletted, black bKGD
-    ftbgn2c16.png 16-bit truecolor, gray bKGD
-    ftbgn3p08.png  8-bit paletted, gray bKGD
-    ftbrn2c08.png  8-bit truecolor, red bKGD
-    ftbwn0g16.png 16-bit gray, white bKGD
-    ftbwn3p08.png  8-bit paletted, white bKGD
-    ftbyn3p08.png  8-bit paletted, yellow bKGD
-    ftp0n0g08.png  8-bit grayscale, opaque
-    ftp0n2c08.png  8-bit truecolor, opaque 
-    ftp0n3p08.png  8-bit paletted, opaque
-    ftp1n3p08.png  8-bit paletted, no bKGD
-
-Here is the correct result of typing "pngtest -m bas*.png" in
+Here is the correct result of typing "pngtest -m *.png" in
 this directory:
 
 Testing basn0g01.png: PASS (524 zero samples)
diff --git a/png.c b/png.c
index fd98988..fb241c0 100644
--- a/png.c
+++ b/png.c
@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 23, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -541,19 +541,19 @@
 png_charp PNGAPI
 png_get_copyright(png_const_structp png_ptr)
 {
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
 #ifdef PNG_STRING_COPYRIGHT
       return PNG_STRING_COPYRIGHT
 #else
 #ifdef __STDC__
    return ((png_charp) PNG_STRING_NEWLINE \
-     "libpng version 1.4.6beta06 - March 8, 2011" PNG_STRING_NEWLINE \
+     "libpng version 1.4.6beta06 - January 23, 2011" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2010 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 ((png_charp) "libpng version 1.4.6beta06 - March 8, 2011\
+      return ((png_charp) "libpng version 1.4.6beta06 - January 23, 2011\
       Copyright (c) 1998-2010 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.");
@@ -573,7 +573,7 @@
 png_get_libpng_ver(png_const_structp png_ptr)
 {
    /* Version of *.c files used when building libpng */
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
    return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
@@ -581,7 +581,7 @@
 png_get_header_ver(png_const_structp png_ptr)
 {
    /* Version of *.h files used when building libpng */
-   PNG_UNUSED(png_ptr)  /* Silence compiler warning about unused png_ptr */
+   png_ptr = png_ptr;  /* Silence compiler warning about unused png_ptr */
    return ((png_charp) PNG_LIBPNG_VER_STRING);
 }
 
diff --git a/pngconf.h b/pngconf.h
index cf9f78a..2040eca 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.4.6beta06 - March 14, 2011
+ * libpng version 1.4.6beta06 - January 23, 2011
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -84,18 +84,6 @@
 
 /* End of material added to libpng-1.2.8 */
 
-/* Added at libpng-1.4.6 */
-#ifndef PNG_UNUSED
-/* Unused formal parameter warnings are silenced using the following macro
- * which is expected to have no bad effects on performance (optimizing
- * compilers will probably remove it entirely).  Note that if you replace
- * it with something other than whitespace, you must include the terminating
- * semicolon.
- */
-#  define PNG_UNUSED(param) (void)param;
-#endif
-/* End of material added to libpng-1.4.6 */
-
 #ifndef PNG_VERSION_INFO_ONLY
 
 /* This is the size of the compression buffer, and thus the size of
diff --git a/pngerror.c b/pngerror.c
index c196b11..aede2fd 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,7 +1,7 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 23, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -306,7 +306,7 @@
    /* Here if not setjmp support or if png_ptr is null. */
    PNG_ABORT();
 #ifndef PNG_CONSOLE_IO_SUPPORTED
-   PNG_UNUSED(error_message) /* Make compiler happy */
+   error_message = error_message; /* Make compiler happy */
 #endif
 }
 
@@ -352,9 +352,9 @@
      fprintf(stderr, PNG_STRING_NEWLINE);
    }
 #else
-   PNG_UNUSED(warning_message) /* Make compiler happy */
+   warning_message = warning_message; /* Make compiler happy */
 #endif
-   PNG_UNUSED(png_ptr) /* Make compiler happy */
+   png_ptr = png_ptr; /* Make compiler happy */
 }
 #endif /* PNG_WARNINGS_SUPPORTED */
 
diff --git a/pngpread.c b/pngpread.c
index a2d8dbf..fa4d3b1 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,7 +1,7 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 23, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -1204,7 +1204,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place tEXt");
-         PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1302,7 +1302,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place zTXt");
-         PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1503,7 +1503,7 @@
    if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
       {
          png_error(png_ptr, "Out of place iTXt");
-         PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+         info_ptr = info_ptr; /* To quiet some compiler warnings */
       }
 
 #ifdef PNG_MAX_MALLOC_64K
@@ -1637,7 +1637,8 @@
          )
 #endif
          png_chunk_error(png_ptr, "unknown critical chunk");
-         PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
+
+      info_ptr = info_ptr; /* To quiet some compiler warnings */
    }
 
 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
diff --git a/pngread.c b/pngread.c
index f4a2956..b2c7391 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 14, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -1337,8 +1337,8 @@
    /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
 
-   PNG_UNUSED(transforms)   /* Quiet compiler warnings */
-   PNG_UNUSED(params)
+   transforms = transforms; /* Quiet compiler warnings */
+   params = params;
 
 }
 #endif /* PNG_INFO_IMAGE_SUPPORTED */
diff --git a/pngrutil.c b/pngrutil.c
index 47395a9..646e1fc 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,7 +1,7 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 23, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -703,7 +703,7 @@
    }
    png_crc_finish(png_ptr, length);
 
-   PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
+   info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 }
 
 #ifdef PNG_READ_gAMA_SUPPORTED
@@ -2505,7 +2505,7 @@
    png_crc_finish(png_ptr, skip);
 
 #ifndef PNG_READ_USER_CHUNKS_SUPPORTED
-   PNG_UNUSED(info_ptr) /* Quiet compiler warnings about unused info_ptr */
+   info_ptr = info_ptr; /* Quiet compiler warnings about unused info_ptr */
 #endif
 }
 
@@ -2961,7 +2961,7 @@
       row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
    }
 #ifndef PNG_READ_PACKSWAP_SUPPORTED
-   PNG_UNUSED(transformations)  /* Silence compiler warning */
+   transformations = transformations; /* Silence compiler warning */
 #endif
 }
 #endif /* PNG_READ_INTERLACING_SUPPORTED */
diff --git a/pngtest.c b/pngtest.c
index c58daf7..3ae78a6 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,7 +1,7 @@
 
 /* pngtest.c - a simple test program to test libpng
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 14, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -387,7 +387,7 @@
 pngtest_flush(png_structp png_ptr)
 {
    /* Do nothing; fflush() is said to be just a waste of energy. */
-   PNG_UNUSED(png_ptr)   /* Stifle compiler warning */
+   png_ptr = png_ptr;  /* Stifle compiler warning */
 }
 #endif
 
diff --git a/pngwrite.c b/pngwrite.c
index dce3845..62d1166 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,7 +1,7 @@
 
 /* pngwrite.c - general routines to write a PNG file
  *
- * Last changed in libpng 1.4.6 [March 8, 2011]
+ * Last changed in libpng 1.4.6 [January 14, 2011]
  * Copyright (c) 1998-2011 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.)
@@ -1451,8 +1451,8 @@
    /* It is REQUIRED to call this to finish writing the rest of the file */
    png_write_end(png_ptr, info_ptr);
 
-   PNG_UNUSED(transforms)   /* Quiet compiler warnings */
-   PNG_UNUSED(params)
+   transforms = transforms; /* Quiet compiler warnings */
+   params = params;
 }
 #endif
 #endif /* PNG_WRITE_SUPPORTED */