CUPERTINO, Calif. – Apple Inc., facing questions from users and tech analysts about reduced performance in older iPhones, acknowledged on Wednesday that its latest software curtails the computing power of some models to prevent unexpected shutdowns.
It was a rare statement from the company that shed light on how Apple internally dealt with a growing user complaint.
“Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices,” Apple wrote, adding that it recently extended the feature to iPhone 7 devices with its iOS 11.2 software update.
The statement came two days after John Poole, founder of the computer-performance testing group Geekbench, wrote a blog post illustrating how iPhone computing performance slows as battery health declines on iPhone 6s and iPhone 7 devices.
Apple said that as iPhone batteries age, or in certain conditions such as cold weather or at low charge, they can struggle to respond to a phone’s power demands.
This can cause the device to unexpectedly shut down to protect “its electronic components,” the company said.
To prevent iPhone 6, iPhone 6s and SE devices from powering off – something that drew complaints last year from Chinese consumer-protection groups –, Apple said it tweaked its iPhone operating system to slow certain tasks that required more computing power than the device could provide.
Evidence of the software change could be seen in power-intensive tasks – such as creating Snapchat filters – that became slower in order to demand less of the system.
Battery life and processing speed are two of the most important features for smartphone users, according to a survey of smartphone buyers by investment bank UBS.
Owners of iPhones have complained for years that their batteries worsen after they update to a new iOS.
Apple has said that battery life may initially decrease after an update as an iPhone rebuilds indexes and caches, but that battery health returns to previous levels within days.
Apple’s newest software, iOS 11, has been troubled by a number of bugs, including one that turned the letter “I” into a question mark and another that crashed some iPhones when third-party apps sent notifications.
The company has issued eight updates since September, two more than it issued through the same period last year for iOS 10.
Poole said many customers, after updating to iOS 11, believe their iPhone is slower because it is old and needs to be replaced, but he said they would be better off replacing the battery.
“We see that once users put a new battery in their phone, battery life and performance goes back up to where they should be,” Poole said.
The issues have stoked frustration among some iPhone users.
Susan Nappa, who uses her iPhone 7 Plus to run her Greenwich, Conn.-based fashion and accessories company, said the device’s internet browser is running slower since she upgraded to iOS 11.
“We’re not giving these devices up, but it’s so frustrating,” said Nappa, who has been using iPhones for nearly a decade.