The DRS_MSG_UPDREFS union defines the request message versions sent to the IDL_DRSUpdateRefs method. Only one version, identified by dwVersion = 1, is currently defined.

 typedef 
 [switch_type(DWORD)] 
 union {
   [case(1)] 
     DRS_MSG_UPDREFS_V1 V1;
   [case(2)]
     DRS_MSG_UPDREFS_V2 V2;
 } DRS_MSG_UPDREFS;

V1: The version 1 request.

V2:  The version 2 request.