diff --git a/ANNOUNCE b/ANNOUNCE
index 2a452e5cf..d2496764c 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,4 +1,4 @@
-Libpng 1.6.15beta04 - November 3, 2014
+Libpng 1.6.15beta04 - November 4, 2014
 
 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.
@@ -36,7 +36,9 @@ Version 1.6.15beta02 [November 1, 2014]
 Version 1.6.15beta03 [November 3, 2014]
   Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
 
-Version 1.6.15beta04 [November 3, 2014]
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 42784455d..ba61d4dbe 100644
--- a/CHANGES
+++ b/CHANGES
@@ -5044,7 +5044,9 @@ Version 1.6.15beta02 [November 1, 2014]
 Version 1.6.15beta03 [November 3, 2014]
   Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
 
-Version 1.6.15beta04 [November 3, 2014]
+Version 1.6.15beta04 [November 4, 2014]
+  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/configure.ac b/configure.ac
index ae873a614..3270961ec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -283,21 +283,17 @@ AC_ARG_ENABLE([arm-neon],
    [case "$enableval" in
       no|off)
          # disable the default enabling on __ARM_NEON__ systems:
-         AC_DEFINE([PNG_USE_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_OPT], [0],
                    [Disable ARM Neon optimizations])
          # Prevent inclusion of the assembler files below:
          enable_arm_neon=no;;
       check)
-         AC_DEFINE([PNG_USE_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
                    [Check for ARM Neon support at run-time]);;
       api)
-         AC_DEFINE([PNG_USE_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
                    [Turn on ARM Neon optimizations at run-time]);;
       yes|on)
-         AC_DEFINE([PNG_USE_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_OPT], [2],
                    [Enable ARM Neon optimizations])
          AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api', if]
@@ -314,7 +310,7 @@ AC_ARG_ENABLE([arm-neon],
 AM_CONDITIONAL([PNG_ARM_NEON],
    [test "$enable_arm_neon" != 'no' &&
     case "$host_cpu" in
-      arm*) :;;
+      arm*|aarch64*) :;;
       *)    test "$enable_arm_neon" != '';;
     esac])
 
diff --git a/pngpriv.h b/pngpriv.h
index 08c7d18c6..aa63cfa47 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -6,7 +6,7 @@
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.6.15 [(PENDING RELEASE)]]
+ * Last changed in libpng 1.6.10 [March 6, 1014]]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -123,8 +123,8 @@
     * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
     * check both variants.
     */
-#  if defined(PNG_USE_ARM_NEON) && (defined(__ARM_NEON__) || \
-     defined(__ARM_NEON)) && defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+   defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 #     define PNG_ARM_NEON_OPT 2
 #  else
 #     define PNG_ARM_NEON_OPT 0