They are hardly limited by that.
There were over 1 billion active iOS devices globally according Apple Q1 2016 report [1]. Android has even more.
[1] http://www.theverge.com/2016/1/26/10828134/apple-earnings-re...
There were over 1 billion active iOS devices globally according Apple Q1 2016 report [1]. Android has even more.
[1] http://www.theverge.com/2016/1/26/10828134/apple-earnings-re...
Second, you also won't convert 50% of those iOS users to use one app. Just not going to happen.
Do you honestly see Snapchat growing to 300 or 500 million DAU?
In fact, according to a marketing company, as of March last year, only 37% of globally active iPhones were even as old as a 5S [1]. Even the iPhone 4S, which did get iOS 8, was on just 5%.
Even if that data is skewed towards newer phones due to the type of sites they market on, it's unlikely that anywhere near half of active devices are running a software version over three years old.
Also, the App Store offers you the last compatible version of the app if your device isn't up to date, and it's possible that that version of Snapchat is still capable of showing ads, although I don't have one around to test it.
[1] http://www.adweek.com/digital/data-37-of-global-iphone-users...
There's more than 1.5 billion Android phones. You don't need 50% of iOS to get to 500M DAU...
https://developer.apple.com/support/app-store/
Looks like ~94% of users are on iOS 9 or iOS 10.