diff --git a/sim/transport/base/CbmEventGenerator.h b/sim/transport/base/CbmEventGenerator.h
index 44d92b570a2068389c188d57e832eec4b15f7083..2457e8468cafe6cf05d57d8dbbae65c9d9af86a6 100644
--- a/sim/transport/base/CbmEventGenerator.h
+++ b/sim/transport/base/CbmEventGenerator.h
@@ -191,7 +191,7 @@ private:
   virtual void MakeVertexInTarget();
 
 
-  ClassDef(CbmEventGenerator, 1);
+  ClassDef(CbmEventGenerator, 2);
 };