diff --git a/ANNOUNCE b/ANNOUNCE
index 56f1acbab..f93ac58ff 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,4 +1,4 @@
-Libpng 1.6.19beta04 - September 26, 2015
+Libpng 1.6.19beta04 - September 27, 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.
@@ -92,7 +92,10 @@ Version 1.6.19beta03 [September 26, 2015]
     warning, updated pngstest-errors.h for the errors detected with the
     new contrib/testspngs PNG test files (John Bowler).
 
-Version 1.6.19beta04 [September 26, 2015]
+Version 1.6.19beta04 [September 27, 2015]
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 58e9bd109..09221b3d5 100644
--- a/CHANGES
+++ b/CHANGES
@@ -5375,7 +5375,11 @@ Version 1.6.19beta03 [September 26, 2015]
     warning, updated pngstest-errors.h for the errors detected with the
     new contrib/testspngs PNG test files (John Bowler).
 
-Version 1.6.19beta04 [September 26, 2015]
+Version 1.6.19beta04 [September 27, 2015]
+  Worked around rgb-to-gray issues in libpng 1.6.  The previous
+    attempts to ignore the errors in the code aren't quite enough to
+    deal with the 'channel selection' encoding added to libpng 1.7; abort.
+    pngvalid.c is changed to drop this encoding in prior versions.
 
 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 35ded08fe..814023591 100644
--- a/contrib/libtests/pngvalid.c
+++ b/contrib/libtests/pngvalid.c
@@ -10960,11 +10960,13 @@ static const color_encoding test_encodings[] =
 /*red:  */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
 /*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
 /*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
+#if PNG_LIBPNG_VER >= 10700
 /* Fake encoding which selects just the green channel */
 /*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */
 /*red:  */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 },
 /*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 },
 /*blue: */ { 0.146774385252705, 0.000000000000000, 0.773892783545073} },
+#endif
 };
 
 /* signal handler