Does anyone know at what ADSM or TSM level DIRMC was added?

We have a potential TSM outsource contract, but the client has LOTS of old
TSM 3.7 and ADSM 3.1.xx versions..I'm talking 100's of 'em. Until we can get
them all rolled over to a supported release, I would like to implement DIRMC
to help them in their restore process, but I don't know/remember what level
DIRMC started being supported. My write-only memory seems to be stopping
short of what-I-had-for-breakfast these days. :-)

TIA,
Bill Boyer
DSS, Inc.