iOS 10.2.1 was released last month but it seems that in a recent statement that Apple has provided to TechCrunch, it turns out that the update has also managed to address these shutdown issues. It does not seem to have fixed it completely, but Apple claims that it has seen a 70-80% reduction in terms of the problem on either model.
Apple also wanted users to know that these shutdowns are not a safety issue, so customers should not be alarmed if it happens. “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.”
So like we said if you are experiencing these random and unexpected shutdowns, then you’ll want to upgrade to iOS 10.2.1 ASAP since it appears that this should address the problem for the majority of iPhone 6/6 Plus and iPhone 6s/6s Plus owners.