diff --git a/TODO b/TODO
index fe46584f..8b1fcd6f 100644
--- a/TODO
+++ b/TODO
@@ -106,6 +106,10 @@ Cross-test versions
   some testing and also be the most common case for having different
   versions and not being able to upgrade.
 
+--no-blocking-io might be broken
+
+  in the same way as --no-whole-file; somebody needs to check.
+
 
 DAEMON --------------------------------------------------------------