I can change the new phone to use 2g - 3g with the same negative result in the house. The booster isn't sold on Amazon anymore but it is describes as " Phonelex ATT T-Mobile Cell Phone Signal Booster 4G LTE 700Mhz FDD Band 12/17 AT&T Cell Signal Booster Repeater Mobile Phone Signal Amplifier AT&T". Yes at least one of the old phones is LTE. I have VoLTE activated now so the phone will work in the house.