I'm doing my first iphone upgrade next week (6 plus is due for delivery on Wednesday). I'm going from the 4 to the 6 plus. I'm just looking through the instructions on how to transfer the data from my 4 to my 6, however I'm also going to a new network and transferring my number across. My plan is to order my new sim with my new network (Three) and when my new phone comes I'm going to call them to ask them to transfer my number from my existing SIM to my new SIM. Will this cause any issues with the setup of my phone? From my previous knowledge of transferring my number I seem to remember that you have a temporary number then once the network have transferred it across it just begins working on the new phone and the texts etc transfer across to the new handset, is that correct? I'll use my iphone 4 until it transfers across and then just start using the 6. Also, I'll be selling the 4. Will the fact that I'm transferring the number cause problems when I wipe everything off the phone before I sell it? ie do you need an active SIM in the phone to be able to do this? Thanks all.