diff --git a/ANNOUNCE b/ANNOUNCE
index e9e5b187d..cdce864aa 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.7.0beta74 - December 15, 2015
+Libpng 1.7.0beta74 - December 18, 2015
 
 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.
@@ -1092,7 +1092,7 @@ Version 1.7.0beta73 [December 11, 2015]
   Changed png_struct->options from png_byte to png_uint_32, to hold
     up to 16 2-bit options.
      
-Version 1.7.0beta74 [December 15, 2015]
+Version 1.7.0beta74 [December 18, 2015]
   Fixed copyright years in source files.
   Removed LE/BE dependencies in pngvalid, to 'fix' the current problem
     in the BigEndian tests by not testing it, making the BE code the same 
@@ -1104,6 +1104,13 @@ Version 1.7.0beta74 [December 15, 2015]
     the 'DIGITIZE' case (the code used prior to 1.7 for rgb_to_gray error
     checks) and changed the check to only operate in non-release builds
    (base build type not RC or RELEASE.)
+  Fixed undefined behavior in pngvalid.c, undefined because
+    (png_byte) << shift is undefined if it changes the signed bit
+    (because png_byte is promoted to int). The libpng exported functions
+    png_get_uint_32 and png_get_uint_16 handle this. (Bug reported by
+    David Drysdale as a result of reports from UBSAN in clang 3.8).
+  This changes pngvalid to use BE random numbers; this used to produce
+    errors but these should not be fixed as a result of the previous changes.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index d1a4fc441..52d8f87d6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -5391,7 +5391,7 @@ Version 1.7.0beta73 [December 11, 2015]
   Changed png_struct->options from png_byte to png_uint_32, to hold
     up to 16 2-bit options.
      
-Version 1.7.0beta74 [December 15, 2015]
+Version 1.7.0beta74 [December 18, 2015]
   Fixed copyright years in source files.
   Removed LE/BE dependencies in pngvalid, to 'fix' the current problem
     in the BigEndian tests by not testing it, making the BE code the same 
@@ -5403,6 +5403,13 @@ Version 1.7.0beta74 [December 15, 2015]
     the 'DIGITIZE' case (the code used prior to 1.7 for rgb_to_gray error
     checks) and changed the check to only operate in non-release builds
    (base build type not RC or RELEASE.)
+  Fixed undefined behavior in pngvalid.c, undefined because
+    (png_byte) << shift is undefined if it changes the signed bit
+    (because png_byte is promoted to int). The libpng exported functions
+    png_get_uint_32 and png_get_uint_16 handle this. (Bug reported by
+    David Drysdale as a result of reports from UBSAN in clang 3.8).
+  This changes pngvalid to use BE random numbers; this used to produce
+    errors but these should not be fixed as a result of the previous changes.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/contrib/libtests/pngvalid.c b/contrib/libtests/pngvalid.c
index 358908f69..f5b11de6c 100644
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -1,7 +1,7 @@
 
 /* pngvalid.c - validate libpng by constructing then reading png files.
  *
- * Last changed in libpng 1.6.21 [(PENDING RELEASE)]
+ * Last changed in libpng 1.5.27 [(PENDING RELEASE)]
  * Copyright (c) 2014-2015 Glenn Randers-Pehrson
  * Written by John Cunningham Bowler
  *