difference between 4.2 and 5.2.1

[Amir Vetry]

Hi team,
I have couple of questions.  Would you please answer it.

Beside supporting more types of NIC card, what other differences are there
between 
FreeBSD 4.2 (or 4.0 series) and 5.2.1 (5.0 Series)?
Also, is multicasting supported on 5.2.1?

Thanks,
-A.