Apple spokeswoman Teresa Brewer said:
We [Apple] recently discovered a manufacturing issue affecting a very limited number of iPhone 5S devices that could cause the battery to take longer to charge or result in reduced battery life. We are reaching out to customers with affected phones and will provide them with a replacement phone.Apple did not provide numbers in terms of iPhone 5s devices affected, nor did it issue a public recall of the type many might be used to: A web page with a list of serial numbers that are affected.
Instead, as noted above, Apple is reaching out to customers itself. While this ensures that the public -- and the media -- does not know how many iPhone 5s smartphones were affected, that fact as well as the term "very limited" also (as Bits noted) implies that the number of affected devices may be relatively small, perhaps in the thousands or tens of thousands.
In September, Apple announced that it had sold nine million new iPhones in its first weekend of sales. Typical of Apple, the company did not, however, break down the numbers to indicate how many were 5s and how many were 5c devices.
The iPhone 5s and its lower-cost sibling, the iPhone 5c, went on sale in October. Despite the 5s' upgraded hardware, both phones are rated, by Apple, with similar battery life. According to the Cupertino, Calif.-based electronics giant, both of its new smartphones can last for up to 250 hours on standby and can be used for up to 10 hours of 3G talk.
They can also play video continuously for 10 hours; meanwhile, both iPhones will also last for 40 hours during continuous audio playback.
On Monday, the company said it sold 33.8 million iPhones -- a record for its fiscal Q4 -- including eight days of 5s and 5c sales.