You need a jailbroken device for this
Here are some tutorials on how to jailbreak:
iOS 9.0 - 9.1
iOS 8.13 - 8.4
Step 1 1. First thing you need to do get is spotify version 3.0.0 or below 2. To do this you first must delete your current spotify (unless it is already at 3.0.0 or below, then go straight to Step 2)
3. Then you must get iFile from cydia (free from this repo: http://repo.biteyourapple.net/) [Hidden Content] 5. Once it is downloaded, open it in iFile. 6. It should appear on your home screen Step 2 1. Add the repo http://repo.hackyouriphone.org/ 2. Then search [Hidden Content] 3. Install the one from hackyouriphone NOT biteyourapple 4. Once you have resprung, go into spotify(v2.4.0) and you should have premium !! Like this for more ! Any problems put in the comments THANKS GUYS **For those of you who are saying this has been done before, I know. I only did this because appcake took away the older versions of spotify so I am showing you a new way of getting old spotify versions**