diff --git a/model/sync-diff-state.h b/model/sync-diff-state.h
index 6a43aef..aed6b32 100644
--- a/model/sync-diff-state.h
+++ b/model/sync-diff-state.h
@@ -86,7 +86,7 @@
   operator += (const DiffState &state);
   
   // from State
-  virtual bool
+  virtual boost::tuple<bool/*inserted*/, bool/*updated*/, SeqNo/*oldSeqNo*/>
   update (NameInfoConstPtr info, const SeqNo &seq);
 
   virtual bool