Geoff Chappell - Software Analyst
The IVersionVector methods are (as ordered in the virtual function table after the IUnknown methods):
HRESULT SetVersion (PCWSTR, PCWSTR);
HRESULT GetVersion (PCWSTR, PWSTR, ULONG *);
The IVersionVector interface is implemented in MSHTML version 5.0 and higher.
Though this interface dates from as long ago as 1999, it was still not documented by Microsoft as late as the January 2007 edition of the Windows Software Development Kit (SDK).