diff --git a/ANNOUNCE b/ANNOUNCE
index 8d6b33f..f92477d 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,5 +1,5 @@
 
-Libpng 1.5.0rc04 - December 28, 2010
+Libpng 1.5.0rc04 - December 29, 2010
 
 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.
@@ -226,7 +226,7 @@
     offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
   Added more blank lines for readability.
 
-version 1.5.0beta25 [December 28, 2010]
+version 1.5.0beta25 [December 29, 2010]
   In pngpread.c: png_push_have_row() add check for new_row > height
   Removed the now-redundant check for out-of-bounds new_row from example.c
 
@@ -478,7 +478,7 @@
   Fixed the clean rule in Makefile.am to remove pngtest-log.txt
   Made minor changes to work around warnings in gcc 3.4
 
-Version 1.5.0rc01 [December 28, 2010]
+Version 1.5.0rc01 [December 29, 2010]
   No changes.
 
 Version 1.5.0rc02 [December 27, 2010]
@@ -487,7 +487,10 @@
 Version 1.5.0rc03 [December 28, 2010]
   Eliminated scripts/*.def and revised Makefile.am accordingly
 
-Version 1.5.0rc04 [December 28, 2010]
+Version 1.5.0rc04 [December 29, 2010]
+  Fixed bug in background transformation handling in pngrtran.c (it was
+    looking for the flag in png_ptr->transformations instead of in
+    png_ptr->flags).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
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diff --git a/CHANGES b/CHANGES
index 61d2567..2a5934c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3125,7 +3125,10 @@
 Version 1.5.0rc03 [December 28, 2010]
   Eliminated scripts/*.def and revised Makefile.am accordingly
 
-Version 1.5.0rc04 [December 28, 2010]
+Version 1.5.0rc04 [December 29, 2010]
+  Fixed bug in background transformation handling in pngrtran.c (it was
+    looking for the flag in png_ptr->transformations instead of in
+    png_ptr->flags).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngrtran.c b/pngrtran.c
index b3425d3..1e22c10 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1068,7 +1068,7 @@
              */
             png_ptr->transformations &= ~PNG_BACKGROUND;
             png_ptr->transformations &= ~PNG_GAMMA;
-            png_ptr->transformations |= PNG_STRIP_ALPHA;
+            png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
          }
 
          /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
@@ -1202,7 +1202,7 @@
 
       /* Handled alpha, still need to strip the channel. */
       png_ptr->transformations &= ~PNG_BACKGROUND;
-      png_ptr->transformations |= PNG_STRIP_ALPHA;
+      png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
    }
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */