Will i lose the notes on my iphone if i update it?

I lost my phone so as a replacement i got my Dads old phone which is fine but he wants the notes from his old iPhone.anyway i know how to do it using mobile me but the problem is it's an incredibly outdated iphone and doesn't have the option it would have if i updated it. So if i was to update the phone would i lose my notes?

Lol no

Yes.
When you update to higher iOS you actually lose EVERYTHING. It's basically restored. So make sure to back everything up.

Of cause u lose everything if you don't back it up

No if you update your iPhone to another iOS nothing will happen. It's just an update, when I updated my iPhone to iOS 5 nothing happened.