In a post on Apple’s Chinese website, “We are including additional diagnostic capability in an iOS software update which will be available next week. This will allow us to gather information over the coming weeks which may potentially help us improve the algorithms used to manage battery performance and shutdown. If such improvements can be made, they will be delivered in future software updates.”
Note that this update does not actually fix the problem, but rather the update is meant to deliver a tool that will gather data and allow Apple to diagnose the problem, after which they will try and see if the issues can be fixed with a software update. We’re not sure how long the entire process will take from start to end, but the diagnostic tool is expected to be part of the upcoming iOS 10.2 update.
In the meantime Apple has offered an explanation as to what might have been the problem, and that is apparently due to a certain battery component being exposed to air longer than it should, thus degrading it and causing the problems today.