karpazoo

hello. i would like to know what is the difference between nod32 ver.4, 5,5,6 and ver. 7. what i am really asking is if there is a difference betwwen their ability to indentify and remove viruses better or they actually work the same. do they have the same scanning and locating viruses? the reason i was asking is that i got a messege one day from my NOD32 ver. 4.2 saying that he upgraded his internal components after he downloaded updates. do i have to upgrade my NOD32 to version 7 or can i stay with ver.4.2? thank you.