iOS 13 — Saving Bandwidth for Fun and Profit

Smartphones behave differently on wifi networks as opposed to cellular networks. The latter is assumed to be expensive and quota-limited, and the former is assumed to be cheap and more or less unlimited. So iOS devices will perform backups and app updates on wifi networks but reduce usage on cellular networks, as well as providing more granular control over data usage for specific apps. Additionally, if an iOS device is connected to a personal hotspot, it knows this is really a cellular service and behaves accordingly.

However some wifi networks are constrained because the Internet service is relatively slow, or because they are cellular connections themselves (such as portable cellular routers). iOS 13 now has a feature which allows usage on such wifi networks to be reduced called Low Data Mode:

1. Tap Settings

2. Tap Wi-Fi

3. Join the required network (if not already) and tap the network name

4. Enable Low Data Mode:
   

Another way to reduce usage temporarily is to use Low Power Mode.