Apple has actually released two sets of numbers: iOS 12 install on devices introduced in the last four years, and iOS 12 installed on devices in total. The former is sitting at 83%, while the latter, like we said, has been installed on 80% of all compatible iOS devices. That’s another advantage that iOS devices have over Android, where Apple typically keeps older devices updated for as long as possible.
Apple is expected to introduce the next major update to iOS in the form of iOS 13 come WWDC 2019. It is unclear what kind of changes we can expect, but last year it was rumored that iOS 12 would be focusing more on overall quality of the update, and that as a result certain features were delayed and potentially pushed back to iOS 13. Either way we’ll have to wait and see, but WWDC is expected to take place in the middle of the year so we shouldn’t have to wait too long to find out.