Commit 6669426ab9 for php.net

commit 6669426ab910ec3ebcfd1c778f3683f384bff43b
Author: Anatoly Pashin <anatoly.pashin@gmail.com>
Date:   Fri Oct 16 19:06:11 2020 +1000

    [ci skip] Make it clear what GD uses instead of resources

    Closes GH-6342.

diff --git a/UPGRADING b/UPGRADING
index e2e17e6239..a15feb826d 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -311,9 +311,10 @@ PHP 8.0 UPGRADE NOTES
     warning.

 - GD:
-  . The GD extension now uses objects as the underlying data structure for
-    images, rather than resources. These objects are completely opaque, i.e.
-    they don't have any methods.
+  . The GD extension now uses a GdImage objects as the underlying data structure
+    for images, rather than resources. These objects are completely opaque, i.e.
+    they don't have any methods. Return value checks using is_resource() should
+    be replaced with checks for `false`.
   . The deprecated function image2wbmp() has been removed.
     RFC: https://wiki.php.net/rfc/image2wbmp
   . The deprecated functions png2wbmp() and jpeg2wbmp() have been removed.