iDownloadblog:

Two weeks ago, the same 84 percent figure was captured by Apple, indicating that the number of users who have upgraded from previous iOS editions to iOS 8, or bought a new device with iOS 8 pre-installed, wasn’t enough to move the needle.

More interesting than that, however, is the latest data point by analysts Mixpanel which basically tells us that the recently-released iOS 8.4 software update now accounts for 40 percent of all iOS usage, just one week after release.

One can guarantee you when using an iOS devices is you can update to the latest version of iOS in day one after it’s released.