AppleiPhone 6 Plus - iOS 11NetworkChange networkmode
Your Apple iPhone 6 Plus automatically joins the fastest data connection available. In some situations, you may want to switch to 2G, 3G or 4G. To manually select the connection type, follow these steps.
Note: Switching down to either 2G or 3G respectively when in either a 2G only or 3G only coverage area will help save battery life.
To start using a faster internet connection again, switch back to a higher network mode.
Go to the Start screen.
Choose Mobile Data.
Choose Mobile Data Options.
Choose Voice & Data.
The Apple iPhone 6 Plus has been set to the lowest possible network mode.