diff --git a/include/sync-state.h b/include/sync-state.h
index c96160e..84c2400 100644
--- a/include/sync-state.h
+++ b/include/sync-state.h
@@ -93,7 +93,7 @@
  * @returns SyncStateMsg msg
  */
 SyncStateMsg &
-operator >> (SyncStateMsg &issm, const State &state);
+operator >> (SyncStateMsg &issm, State &state);
 
 namespace Error {
 /**