Well, Rod, I would have to guess it is a term of (black) architecture.

I would also be guessing that it means designing software to be backwards-compliant, or compatible with the limitations of older hardware/software configurations. Now I suppose you will tell me it's all about legal adoption procedures

edit: Well, people, make your guesses before you LIU as I just have - you will be at least as likely to get it right as I was...!