--- openflow-2013-01-18-4.h	2015-07-23 09:54:17.392479372 -0700
+++ openflow-2013-02-04.h	2015-07-23 09:54:17.400479372 -0700
@@ -2744,6 +2744,7 @@
 enum ofp_controller_role_reason {
     OFPCRR_MASTER_REQUEST = 0,  /* Another controller asked to be master. */
     OFPCRR_CONFIG         = 1,  /* Configuration changed on the switch. */
+    OFPCRR_EXPERIMENTER   = 2,  /* Experimenter data changed. */
 };
 
 /* Role status event message. */