Well, the first thing to say is that we've worked hard to maintain compatibility, so that any program written with an earlier version of Mathematica can run without change in 3.0, and any notebook can be converted.
-- Stephen Wolfram
   
Stephen Wolfram   Name:
Stephen Wolfram
Type:
Scientist
Nationality:
English
Birth:
August 29, 1959
https://www.nutquote.com/quote/Stephen_Wolfram