How to replace existing iphone with new one: If they have different OS

[nippyjun]

I currently have the original iphone. I'm getting the new iphone 3gs.

Does my original iphone need to have os3 on it to be able to restore the new phone from the backup of the old phone?

 

[Revelation78]

That's actually a good question and one I don't know - I'm interested in finding out. The good thing you can always update your OS on the 17th and upgrade your device on the 19th to be safe.