Document an incompatible change in the previous push.

The old syntax for setting HTML link attributes is no longer
supported.  Existing links will not fail, but the attributes specified
in the old way will be ignored.

ORGWEBPAGE/Changes.org

@@ -17,6 +17,22 @@
   :END:
 ** Overview
 ** Incompatible changes
+*** Old syntax for link attributes disbandoned
+    There used to be a syntax for settint link attributes for
+    HTML export by enclosing the attributes into double braces
+    and adding them to the link itself, like
+#+begin_example
+[[./img/a.jpg{{alt="an image"}}] ]
+#+end_example
+
+This syntax is not longer supported, use instead
+
+#+begin_example
+#+ATTR_HTML: alt="an image"
+[[./img/a.jpg] ]
+#+end_example
+
+
 ** Details
 *** Captions and attributes for figures and tables.