update docs

README.md

@@ -74,6 +74,10 @@ You **DO NOT NEED TO KNOW** these details.
 They're provided for the sake of understanding what happens "under the hood"
 to help you make better choices "in the seat".
 
+**Note**: The actual code could stand to be tidied up.
+It does need to continue to support Greenlock v2 for a few more months,
+so I didn't rip out the old v1 -> v2 -> v3 cruft yet.
+
 # Parameters
 
 | parameters        | example                                                  | notes            |