8830 Device & DT Mgr. S/W ???

[LabLuvr]

I just activated an 8830 (in the store) that my friend gave me. I plan to use it while I research which smartphone I will buy. I want to update the "Device" SW to the newest i.e. 4.2.2 to 4.5. Is this a good idea? Also, I only have the Desktop Mgr. SW CD he gave to me (2-3 years old). Should I also down load the newest version 5.0 ( I think)? I am asking because I have found that sometimes the newest SW isn't always the most reliable, etc. However, I do want to get the most out of this older device while I'm using it (2-3 months). BTW, I had my old phone's address book (300+) transferred in the store. Should I try to use the "BackUp Assistant" or the DeskTop Mgr. SW to keep my contacts safe and up to date? Thanks for any advice or help.