Still no. If an iOS app is using your microphone while backgrounded, your phone's taskbar at the top of the screen will be red. iOS does not allow apps to use the microphone while the screen is off. The microphone thing is a myth fueled by paranoia and confirmation bias. FB already has plenty of data on you and doesn't need to run NLP on everything you say in order to show you relevant ads.

> iOS does not allow apps to use the microphone while the screen is off.

Isn't the screen off in nearly all of the legitimate uses of a microphone, ie. "I'm replicating the ux of a phone call in my chat app"?

Well I have messenger lite on Android and they, as the parent says, "ask permission to listen to your microphone". Presumably they do voice chat, which needs that permission, surely.