hi friends.. i have a blackberry 7130g wireless handheld (EDGE) v4.1.0.377 and platform is 2.1.0.39..

i want to upgrade OS to 4.2.xxx (which one is suitable).. can i do it?
if so; does my blackberry's pin number chnage?
does it work in my blackberry ?.. and what are the benefits of 4.2xxx ?

i m waiting for your helps ... thanks