Fix Slow Wi-Fi Speeds
If your Wi-Fi network is running slow, you can have your iPhone automatically switch to faster LTE speeds. Just go to Settings >> Cellular >> Wi-Fi Assist. However, you should be aware that leaving Wi-Fi Assist on can absolutely devour your data. Wi-Fi Assist automatically determines when it’s necessary and flips on and off on its own, so you are unlikely to know when Assist is in effect. If you have a limited data plan, it could tally up a significant amount of overage fees.