It was previously discovered that a large number of iPhone 6s users were experiencing unexpected shutdowns. Apple has since then launched a repair program to resolve this issue for some users after finding out that the issue was more widespread than originally thought.
However, Apple said (via TechCrunch) that the issue has been resolved for most users with the iOS 10.2.1 software update.
After letting the fix simmer on customer devices, Apple now has statistics to share on how it has improved the issue, citing 80% reduction on iPhone 6S and 70% reduction on iPhone 6 devices.
The fix appears to fix devices that were recently affected. If you’re still having issues with shutdowns even after the software update, you should check your serial number with Apple to see if your device is eligible for a replacement.
Here’s Apple’s full statement:
With iOS 10.2.1, Apple made improvements to reduce occurrences of unexpected shutdowns that a small number of users were experiencing with their iPhone. iOS 10.2.1 already has over 50% of active iOS devices upgraded and the diagnostic data we’ve received from upgraders shows that for this small percentage of users experiencing the issue, we’re seeing a more than 80% reduction in iPhone 6s and over 70% reduction on iPhone 6 of devices unexpectedly shutting down.
We also added the ability for the phone to restart without needing to connect to power, if a user still encounters an unexpected shutdown. It is important to note that these unexpected shutdowns are not a safety issue, but we understand it can be an inconvenience and wanted to fix the issue as quickly as possible. If a customer has any issues with their device they can contact AppleCare.
TechCrunch believes that the issue was due to spikes in activity, which created a power management problem. Apple has included a power management fix in iOS 10.2.1 that should resolve this issue.