From what version of NT FastIoDetachDevice routine was supported ?

Hi all:
I read the Filepro Monitor sourcecode ( from www.sysinternas.com ) and
the sWindows NT File System Internalst. File monitor said that the
FastIoDetachDeivce was supported previous to NT 4.0, but sWindows NT File
System Internalstsaid that it was not supported until 4.0, how is it ?