I am planning on buying my Mum a phone and it looks like the best option as far as iPhones goes in terms of getting a new one is a 5S 16GB. By best I mean she needs the most basic option. I've had a look at second hand iPhones in local shops here in the U.K. but even the best condition ones I'm not too keen on. If I get her a 5S on contract what is the latest version of iOS that is recommended. Will iOS 9 run fine on it. Also I'm in the U.K. The best deal I've seen is with O2 which is £168 for the phone and then £12 per month for 500. Mins., 500 MB of data and unlimited texts on a 24 month contract. Anyone know of any better deals. The texts and data are not that important and minutes can be around the 500 mark. She is not going to be using any other apps other then Whats App and maybe Skype. She is primarily going to use it for making the odd phone call and send a few Whats App messages. Any help/advice would be appreciated. Thanks.