Instructions

When "Data Saving" is on, apps in the background will not be able to use mobile
data. Application in the foreground will decide if data-saving measures are to be
taken, e.g. reducing image resolutions. In addition, you will not be able to use the
network tethering function, and the status bar will display the data saving icon.
You can also set an unrestricted app. When Data Saving is on, those unrestricted
ones will be able to receive new messages over cellular data.
"Settings" > "SIM Card & Cellular Network" >"Data Usage">"Data Saving".