So a little backstory: A customer came in wondering why their apps were either running slow or not at all, even after they reset their device. After checking it myself I noted that the applications that ran without issue were ones that required no internet whatsoever. Youtube, for instance, crashed both in safari and in app. I've searched for quite a while and most forums I've browsed have stated that it's 9.3.5. Obviously there's no signed previous versions, and I'm new on the idea of jailbreaking a device (especially 9.3.5) in order to roll it back. I've reset the device myself using iTunes, but to no avail. Any help provided with people who have perhaps had the same issues would be greatly appreciated.