If you are running iOS 9 on an iPhone or iPad and have purchased a cellular data plan, here is an article you will want to read. There is a new "feature" in iOS 9 that automatically switches your device from wifi to cellular if iOS 9 deems the wifi signal to be too weak. It is called "wi-fi assist". Jim Hamm does not like this "feature". He travels frequently, and wifi signals are often weak in hotels and RV parks. He does not want his iPhone or iPad to switch to cellular without his OK since he could easily burn through his cellular plan data cap and not even realize it. Fortunately, this "feature" can be turned off.