Build/Product/Version/Point releases

I'd like to obtain from Bentley the meaning of the various product build numbers.

For instance MicroStation: "08"."11"."09"."459"

We know the 459 is a by Bentley definition a "Point Release" but to assist our strategy documentation, we would like a detailed description/definition for each of the other numbers. I've looked through various help files and other locations and have not found anything, but I've seen it before someplace.

Thanks in advance.