Transfer data to new iPhone with outdated software?

[iMore Question]

But if my new iPhone is using an old software system it is not possible to transfer data from the previous iPhone. Then I am told to upgrade my new iPhone (with the outdated system) to latest software system which means that I have to install it as a new iPhone. After this installation how do I then transfer the data from my old iPhone?

 

[kch50428]

Update old phone to latest iOS... back-up to iTunes... update new phone to latest iOS... restore back-up of old phone to new phone...