Undoubtedly the weakest point of current devices is their battery or at least it seems that way if we take into account the amount of news that comes to light due to battery problems. All companies are being affected by problems in their batteries and in the case of Apple we have the recent case of the MacBook Pro with Touch Bar of this past 2016 that put on the table some really bad Consumer Reports results (although it has been rectified later on) or the iPhone 6s battery replacement program, To which it was rumored, the previous models could be added, the iPhone 6, but in the end all this seems to remain there, rumors ...
In this case, what is clear to us is that the batteries have to go through strict controls before being added to the equipment and even so they can have a fault as many users would be reporting. In this way Apple has always been an exemplary company and when they detect a problem or possible problem they add a replacement program for affected users. In this case, the one that affects the iPhone 6s models is this:
Apple has determined the possibility of a very small number of iPhone 6s devices turning off unexpectedly. This is not a security issue and only affects devices that belong to a limited range of serial numbers manufactured between September and October 2015. If you have experienced this issue, please enter your iPhone 6s serial number below to check if it is fit for free battery replacement.
On the other hand, it seems that the previous model, the iPhone 6 or some units sold could have the same battery problem and rumors warned that Apple could add them to this replacement program but it seems that in the end it will be nothing ... This is not officially confirmed by the company as of today. but they are not expected to do so either since "if there is no fault" there is nothing they can say.
Axiomatic if it is called an iPhone S replacement plan it is not called an iPhone 6 replacement plan