Apple says 50% of devices upgraded to iOS 9


Apple also announced the fastest iOS adoption ever, with more than 50 percent of devices already using iOS 9.

I think it's interesting iOS 9 had driven fast upgrades. To me, anyway, iOS 9 doesn't seem to have that killer feature to get drive people to upgrade faster than normal. I'd guess a major reason is the upgrade is much smaller and requires less free space than previous versions. With iOS 8 I knew many people who held off upgrading because they first had to take the time to free up a lot storage on their device.