What is the timetable to use a new api on iOS and what is it on Android(assuming you want to target the majority of the market)? How does it help the ecosystem

What is the timetable to use a new api on iOS and what is it on Android(assuming you want to target the majority of the market)? How does it help the ecosystem to have 4-5 different shells running on top of Android? It makes the word Android mean less to people. So I can probably run the same apps but my interaction with the phone is different and upgrades take much longer to be verified. These aren't dire problems but I think a lot of people would like to see them addressed in some way.