koz

I really want to upgrade to jailbreak 4.3.1.  However, I'm confused!
I have my jailborken iPhone 4.2.1, do I still need to upgrade to 4.3.1 in iTune first before I start the above jailbreak process?
Because my iPhone is jailborken, can I still use iTune to upgrade my iPhone to 4.3.1?
What will happen after my 4.2.1 jailborken iPhone upgrade to 4.3.1? I mean does the upgrade will make my iPhone become un-jailbreak?
Thanks very much.

koz

Sorry! I have one more question.
I used the GreenPois0n jailbreak before. Does it make any difference?  Can I use RedSn0w jailbreak now? Thanks