New iPhone and operating system launch, but your phone seems to slow down. Coincidence. May want to purge your phone before an update. The more storage you have used up, the slower your phone will go. Your home wifi could affect your phone as well, so make sure you invest in your wifi router. See what else you can do for your phone.https://www.nytimes.com/2017/11/15/technology/personaltech/new-iphones-slow-tech-myth.html