Apple had offered to settle the controversy with the issue of batteries and the “slow” iPhone was a replacement at cost, for only $29. This battery replacement program serves, according to Apple, that customers who have lost confidence in the company recover it, and to show that the Cupertino have not acted in bad faith in this matter.
Apple announced this replacement program for the end of January, but later announced that the beginning of it is from now on, because the preparations they needed to start it have taken less time than they had originally estimated.
Apple has announced the start of the program in the United States. Although it warns that the stock of batteries will be limited in an initial phase, as the necessary components are coming to the Apple Store and authorized technical services, users can go accessing the battery change for that price of $29. This announcement for the United States has not been accompanied by when it will begin for the rest of the world. Presumably, as they receive batteries the program will be extended to other countries. We must wait until the next working day to know if the Apple Store in other countries started to accept these requests.
The program is only valid for the iPhone 6 and later, but as long as the tests performed by Apple technicians result in the battery of the device is degraded and needs the change. According to Apple this is the reason why some of the functions of the iPhone slow down, and that is why it is an essential requirement for the replacement of the battery.