diff --git a/src/runtime2/communication.rs b/src/runtime2/communication.rs
index 803db6e48ef4c9ef920d8ffc26b4a86a2d13ad86..6040e234106bbb37dc09f30569661b9890803fcc 100644
--- a/src/runtime2/communication.rs
+++ b/src/runtime2/communication.rs
@@ -177,6 +177,7 @@ pub enum ControlMessageContent {
 #[derive(Copy, Clone, Debug)]
 pub struct ControlMessageClosePort {
     pub closed_in_sync_round: bool, // needed to ensure correct handling of errors
+    pub registered_round: Option<u32>,
 }
 
 // -----------------------------------------------------------------------------