From the Apple support page for the iPhone 6s unexpected shutdown problem:

Apple has determined that a very small number of iPhone 6s devices may unexpectedly shut down. This is not a safety issue and only affects devices within a limited serial number range that were manufactured between September and October 2015.

If you have experienced this issue, please visit an Apple Retail Store or an Apple Authorized Service Provider and have your device’s serial number checked to confirm eligibility for a battery replacement, free of charge.

And from the Apple support page for the Multi-Touch repair program for the iPhone 6 Plus:

Apple has determined that some iPhone 6 Plus devices may exhibit display flickering or Multi-Touch issues after being dropped multiple times on a hard surface and then incurring further stress on the device.

If your iPhone 6 Plus is exhibiting the symptoms noted above, is in working order, and the screen is not cracked or broken, Apple will repair your device for a service price of $149.

Curious how they verify the “dropped multiple times on a hard surface” issue. There a sensor for that?