+; Drop v3 (and older) keys. These are long considered insecure, so unless there
+; is a good reason you should accept this default.
+drop_v3=true
+; Only allow keys that already exist to be update; silently drop the addition
+; of any key we don't already know about. Useful for allowing updates to
+; curated keys without the addition of new keys.
+;update_only=false