diff --git a/doc/todo/aeson_2.0.mdwn b/doc/todo/aeson_2.0.mdwn
new file mode 100644
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@@ -0,0 +1,5 @@
+Need to update to allow building with aeson 2.0.
+
+I have a patch in my mailbox from sternenseemann that
+mostly gets there, but it needs some revision to fix a problem I spotted.
+--[[Joey]]