(Now Android 11 and devices with 5G(NR) are ed)
This app will help You change network to 4G/3G/2G and stay in chosen network.
No more auto switch betwen 4G/3G.
If you have free 4G data transfer and You must pay for 3G, just set up your network for only LTE.
Force LTE not every phone. It is depends what phone brand your phone is.
Some phone brands block opportunity to force switch network.
Pleas don't rate down this app if is not working on your phone because it is not depends from Us.