diff --git a/diagrams/__init__.py b/diagrams/__init__.py
index 51396431..a9e0f0c1 100644
--- a/diagrams/__init__.py
+++ b/diagrams/__init__.py
@@ -60,6 +60,8 @@ class Diagram:
         "height": "1.4",
         "labelloc": "b",
         # imagepos attribute is not backward compatible
+        # TODO: check graphviz version to see if "imagepos" is available >= 2.40
+        # https://github.com/xflr6/graphviz/blob/master/graphviz/backend.py#L248
         # "imagepos": "tc",
         "imagescale": "true",
         "fontname": "Sans-Serif",