How new of an iPhone do you need for STEPN?

STEPNSTEPN
$1.37
‑5.63%
self.StepN6d ago
My wife keeps earning 30-50% less gst than she is supposed to earn. Everything seems to be working fine. The distance is normal and it doesn’t say moonwalking. Yet the gst earned always comes out low. She has an iPhone XS. Does she need a newer phone? All of her settings were the same as mine except roaming which I just turned on. I don’t think that’s it either since I use very little roaming data.