diff --git a/contrib/libtests/makepng.c b/contrib/libtests/makepng.c
index 60d96d198..9dff04846 100644
--- a/contrib/libtests/makepng.c
+++ b/contrib/libtests/makepng.c
@@ -3,7 +3,7 @@
 /* Copyright: */
 #define COPYRIGHT "\251 2013,2015 John Cunningham Bowler"
 /*
- * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.20 [November 24, 2015]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
diff --git a/contrib/libtests/pngimage.c b/contrib/libtests/pngimage.c
index b03b33f67..ff0b89ecf 100644
--- a/contrib/libtests/pngimage.c
+++ b/contrib/libtests/pngimage.c
@@ -2,7 +2,7 @@
  *
  * Copyright (c) 2015 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.18 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.18 [July 23, 2015]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
diff --git a/contrib/libtests/pngstest.c b/contrib/libtests/pngstest.c
index 3374c7202..0febb63a1 100644
--- a/contrib/libtests/pngstest.c
+++ b/contrib/libtests/pngstest.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2013-2015 John Cunningham Bowler
  *
- * Last changed in libpng 1.6.19 [(PENDING RELEASE)]
+ * Last changed in libpng 1.6.19 [November 12, 2015]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
diff --git a/contrib/libtests/pngvalid.c b/contrib/libtests/pngvalid.c
index f5b11de6c..d9913dac0 100644
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -2,7 +2,7 @@
 /* pngvalid.c - validate libpng by constructing then reading png files.
  *
  * Last changed in libpng 1.5.27 [(PENDING RELEASE)]
- * Copyright (c) 2014-2015 Glenn Randers-Pehrson
+ * Copyright (c) 2014-2016 Glenn Randers-Pehrson
  * Written by John Cunningham Bowler
  *
  * This code is released under the libpng license.
diff --git a/png.c b/png.c
index 008ad0641..d38201b3d 100644
--- a/png.c
+++ b/png.c
@@ -2,7 +2,7 @@
 /* png.c - location for general purpose libpng functions
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
@@ -705,15 +705,15 @@ png_get_copyright(png_const_structrp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.7.0beta76 - December 30, 2015" PNG_STRING_NEWLINE \
-     "Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson" \
+     "libpng version 1.7.0beta76 - January 2, 2016" PNG_STRING_NEWLINE \
+     "Copyright (c) 1998-2002,2004,2006-2016 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 1.7.0beta76 - December 30, 2015\
-      Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson\
+      return "libpng version 1.7.0beta76 - January 2, 2016\
+      Copyright (c) 1998-2002,2004,2006-2016 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
 #  endif
@@ -987,7 +987,7 @@ png_colorspace_set_gamma(png_const_structrp png_ptr,
    png_colorspacerp colorspace, png_fixed_point gAMA)
 {
    /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
-    * occur.  Since the fixed point representation is asymetrical it is
+    * occur.  Since the fixed point representation is asymmetrical it is
     * possible for 1/gamma to overflow the limit of 21474 and this means the
     * gamma value must be at least 5/100000 and hence at most 20000.0.  For
     * safety the limits here are a little narrower.  The values are 0.00016 to
diff --git a/png.h b/png.h
index 0d2c09db2..632552a8f 100644
--- a/png.h
+++ b/png.h
@@ -1,9 +1,9 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.7.0beta76, December 30, 2015
+ * libpng version 1.7.0beta76, January 2, 2016
  *
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
@@ -12,7 +12,7 @@
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *   libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.7.0beta76, December 30, 2015:
+ *   libpng versions 0.97, January 1998, through 1.7.0beta76, January 2, 2016:
  *     Glenn Randers-Pehrson.
  *   See also "Contributing Authors", below.
  */
@@ -25,8 +25,8 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.0.7, July 1, 2000, through 1.7.0beta76, December 30, 2015, are
- * Copyright (c) 2000-2002, 2004, 2006-2015 Glenn Randers-Pehrson, are
+ * libpng versions 1.0.7, July 1, 2000, through 1.7.0beta76, January 2, 2016, are
+ * Copyright (c) 2000-2002, 2004, 2006-2016 Glenn Randers-Pehrson, are
  * derived from libpng-1.0.6, and are distributed according to the same
  * disclaimer and license as libpng-1.0.6 with the following individuals
  * added to the list of Contributing Authors:
@@ -218,7 +218,7 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    December 30, 2015
+ *    January 2, 2016
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
@@ -288,7 +288,7 @@
 /* Version information for png.h - this should match the version in png.c */
 #define PNG_LIBPNG_VER_STRING "1.7.0beta76"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.7.0beta76 - December 30, 2015\n"
+     " libpng version 1.7.0beta76 - January 2, 2016\n"
 
 #define PNG_LIBPNG_VER_SONUM   17
 #define PNG_LIBPNG_VER_DLLNUM  17
@@ -710,7 +710,9 @@ typedef struct png_text_struct
                               0: zTXt, deflate
                               1: iTXt, none
                               2: iTXt, deflate  */
-   png_byte  location;     /* before/after PLTE or after IDAT */
+   png_byte  location;     /* 1: PNG_HAVE_IHDR
+                              2: PNG_HAVE_PLTE
+                              8: PNG_AFTER_IDAT */
    png_charp key;          /* keyword, 1-79 character description of "text" */
    png_charp text;         /* comment, may be an empty string (ie "")
                               or a NULL pointer */
diff --git a/pngchunk.h b/pngchunk.h
index b3463b95a..4495c9b57 100644
--- a/pngchunk.h
+++ b/pngchunk.h
@@ -2,7 +2,7 @@
 /* pngchunk.h - PNG chunk descriptions
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 2015 Glenn Randers-Pehrson
+ * Copyright (c) 2016 Glenn Randers-Pehrson
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
diff --git a/pngconf.h b/pngconf.h
index a74d185f7..d12fe64af 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,9 +1,9 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.7.0beta76, December 30, 2015
+ * libpng version 1.7.0beta76, January 2, 2016
  *
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngerror.c b/pngerror.c
index 871b97e26..41bd4d038 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -2,7 +2,7 @@
 /* pngerror.c - stub functions for i/o and memory allocation
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngget.c b/pngget.c
index 9c3d7e9d6..924b71cc1 100644
--- a/pngget.c
+++ b/pngget.c
@@ -2,7 +2,7 @@
 /* pngget.c - retrieval of values from info struct
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngmem.c b/pngmem.c
index 2888a5353..e182e71c1 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -2,7 +2,7 @@
 /* pngmem.c - stub functions for memory allocation
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngpread.c b/pngpread.c
index 8949c7572..c7dc3178f 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -2,7 +2,7 @@
 /* pngpread.c - read a png file in push mode
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngpriv.h b/pngpriv.h
index f417bd317..fd0132585 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -2,7 +2,7 @@
 /* pngpriv.h - private declarations for use inside libpng
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
@@ -277,7 +277,9 @@
 #endif
 
 /* The affirm mechanism results in a minimal png_error() in released versions
- * ('STABLE' versions) and a more descriptive PNG_ABORT in all other cases.
+ * ('STABLE' versions) and a more descriptive PNG_ABORT in all other cases,
+ * when the "condition" is false (zero).  If "condition" is true (nonzero),
+ * then the affirm mechanism does nothing.
  *
  * The PNG_RELEASE_BUILD macro, defined above, controls the behavior of
  * 'affirm': if set to 1 affirm will call png_error (or png_err) rather than
@@ -905,14 +907,14 @@ PNG_INTERNAL_FUNCTION(png_uint_16, png_u16_affirm,(png_const_structrp png_ptr,
 #  define png_check_byte(pp, b) (png_byte_affirm((pp), PNG_SRC_LINE, (b)))
 #  define PNG_BYTE(b)           ((png_byte)((b) & 0xFFU))
 #  define PNG_UINT_16(u)        ((png_uint_16)((u) & 0xFFFFU))
-#elif !(defined PNG_REMOVE_CASTS)
+#elif !(defined PNG_REMOVE_CASTS) /* && !RANGE_CHECK */
 #  define png_check_bits(pp, u, bits) (((1U<<(bits))-1U) & (u))
 #  define png_check_char(pp, c) ((char)(c))
 #  define png_check_byte(pp, b) ((png_byte)(b))
 #  define png_check_u16(pp, u)  ((png_uint_16)(u))
 #  define PNG_BYTE(b)           ((png_byte)((b) & 0xFFU))
 #  define PNG_UINT_16(u)        ((png_uint_16)((u) & 0xFFFFU))
-#else
+#else /* !RANGE_CHECK */
    /* This is somewhat trust-me-it-works: if PNG_REMOVE_CASTS is defined then
     * the casts, which might otherwise change the values, are completely
     * removed.  Use this to test your compiler to see if it makes *any*
diff --git a/pngread.c b/pngread.c
index c6781c472..349810a02 100644
--- a/pngread.c
+++ b/pngread.c
@@ -2,7 +2,7 @@
 /* pngread.c - read a PNG file
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngrio.c b/pngrio.c
index 952004d5e..9ac4781fa 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -2,7 +2,7 @@
 /* pngrio.c - functions for data input
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngrtran.c b/pngrtran.c
index c988ba637..77f98d426 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -2,7 +2,7 @@
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngrutil.c b/pngrutil.c
index 24bc7bed6..1ee3e9efc 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -2,7 +2,7 @@
 /* pngrutil.c - utilities to read a PNG file
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngset.c b/pngset.c
index 33fa8b20a..e551489cb 100644
--- a/pngset.c
+++ b/pngset.c
@@ -2,7 +2,7 @@
 /* pngset.c - storage of image information into info struct
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngstruct.h b/pngstruct.h
index 071a20fb7..033147400 100644
--- a/pngstruct.h
+++ b/pngstruct.h
@@ -2,7 +2,7 @@
 /* pngstruct.h - header file for PNG reference library
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngtest.c b/pngtest.c
index 62a4f40a7..3e36ba9d8 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -2,7 +2,7 @@
 /* pngtest.c - a simple test program to test libpng
  *
  * Last changed in libpng 1.5.25 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngtrans.c b/pngtrans.c
index a1197ad14..3aafb1afb 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,8 +1,8 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngwio.c b/pngwio.c
index 038cad0b4..e68cd5280 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -2,7 +2,7 @@
 /* pngwio.c - functions for data output
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngwrite.c b/pngwrite.c
index fa312f239..b0c0b5dd4 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -2,7 +2,7 @@
 /* pngwrite.c - general routines to write a PNG file
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngwtran.c b/pngwtran.c
index 324f4cea3..b4494aecc 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -2,7 +2,7 @@
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
  * Last changed in libpng 1.6.17 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *
diff --git a/pngwutil.c b/pngwutil.c
index 8391e7e80..b2a0e7e5b 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -2,7 +2,7 @@
 /* pngwutil.c - utilities to write a PNG file
  *
  * Last changed in libpng 1.7.0 [(PENDING RELEASE)]
- * Copyright (c) 1998-2002,2004,2006-2015 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2002,2004,2006-2016 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.)
  *