The DRS_MSG_GETCHGREQ union defines request messages that are sent to the IDL_DRSGetNCChanges method. There are no V1, V2, V3, V6, or V9 messages.

 typedef 
 [switch_type(DWORD)] 
 union {
   [case(4)]
     DRS_MSG_GETCHGREQ_V4 V4;
   [case(5)]
     DRS_MSG_GETCHGREQ_V5 V5;
   [case(7)]
     DRS_MSG_GETCHGREQ_V7 V7;
   [case(8)]
     DRS_MSG_GETCHGREQ_V8 V8;
   [case(10)]
     DRS_MSG_GETCHGREQ_V10 V10;
   [case(11)]
     DRS_MSG_GETCHGREQ_V11 V11;
 } DRS_MSG_GETCHGREQ;

V4: Version 4 request (Windows 2000 operating system SMTP replication [MS-SRPL]).

V5: Version 5 request (Windows 2000 RPC replication).

V7: Version 7 request (Windows Server 2003 operating system SMTP replication [MS-SRPL]).

V8: Version 8 request (Windows Server 2003 RPC replication).

V10: Version 10 request (Windows Server 2008 R2 operating system RPC replication).

V11: Version 11 request (Windows Server v1803 operating system RPC replication).