[general8bitso]

I keep seeing the 1 billion devices line being touted, but what is the breakdown by iOS version?

Kind of useless if you can no longer install any new apps.

That probably includes obsolete iPads too.

[askafriend]

Here's the breakdown on Dec 3rd, 2018: https://photos5.appleinsider.com/gallery/28764-45426-ios12-a...

iOS adoption of new versions is extremely strong and has typically always been that way. Rate of adoption is fast as well. From release of a new version to 50% adoption is often just a few weeks.