[devel] Check for up->location !PNG_AFTER_IDAT when writing unknown chunks

before IDAT.
diff --git a/CHANGES b/CHANGES
index 3e24f3a..0312d86 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3368,6 +3368,8 @@
   Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
     from pngpriv.h to png.h because they must be visible to applications
     that call png_set_unknown_chunks().
+  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+    before IDAT.
 
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