A range of smartphone models are used., page-51

Never once said that the app would be compromised by different phones. However this would have to be proven by testing and solid results rather than just saying all phones have microphones and you can hear people when they speak into them. People on HC may accept that but not the FDA and that is why they have qualified people that review your submission instead of the challenged people on this forum.

Would you want a medical device used on you that was approved by the likes of Sabre et al. She'll be right mate. Give it the tick of approval and we can knock of early and go down to the pub.