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
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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