Apple has announced the random shutdown issues plaguing some iPhone 6s units could be more widespread than first believed.
Apple initially said that it found that battery components in a particular batch of iPhones were exposed to the air for too long before assembly, causing the batteries to cut out. It has now updated its statement to say that some customers with phones from outside this batch have also experienced shutdowns, and that it will be issuing an iOS update to help track down the cause.
In a support document posted on one of its international support sites, but not yet on the U.S. site, the Cupertino firm says a software fix may alleviate the issue for units not involved in the original batch of units.
Outside the affected batch, a small number of customers reported an unexpected shutdown. Some of these shutdowns may be normal, because the iPhone will shut down to protect its electronic components. To gather more information, we will add an additional diagnostic feature to the iOS software update that is released next week. This feature collects a variety of information in the coming weeks that may help us improve algorithms for managing battery performance and shutdown operations. If such improvements can be achieved, we will deliver them through further software updates.
Apple previously launched a free repair program for iPhone 6s units that contained faulty batteries, manufactured in the September to October 2015 timeframe. They now offer a website to check your iPhone 6s device to see if it is eligible for the free repairs.