Apple is often accused of deliberately slowing down older iPhones, with conspiracy theorists claiming it is a ruse to force customers to upgrade.
Now, it appears that the theory is true, at least in part. Apple has admitted that it deliberately limits the performance of iPhones when a battery gets too old.
It installed the “feature” on the iPhone 6, 6S and SE in 2016 during a software update and the iPhone 7 this month with the release of iOS 11.2. New devices will also receive the update in the future, Apple confirmed.
Apple is actively slowing phones down to help their batteries last longer.
“Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices,” an Apple spokesman said.
Older phone batteries struggle to supply the required maximum current needed to power the phone processor at full speed, causing it to shut down unexpectedly.
By slowing the performance, the phone does not need the maximum current, and therefore won’t switch off without any warning, as many customers had been reporting even when they had up to 40 percent battery capacity.
The new feature was first spotted by Geekbench, a tech watchdog and reviews site. It found that, on certain versions of iOS, phones with older batteries would achieve much lower performance scores.
While smartphone battery capacity decreases as it ages, processing power is not meant to be affected in the same way. But speed may be limited in order to prolong the battery life, according to the figures.
Apple issued the first software update when iPhone 6 and iPhone 6s owners began reporting “sudden shutdown”.
“It appears the problem is widespread, and will only get worse as phones (and their batteries) continue to age,” wrote Geekbench developer John Poole in a blog post.
“I believe (as do others) that Apple introduced a change to limit performance when battery condition decreases past a certain point.”
Mr Poole suggested that the problem could be rectified by replacing the battery.
“This fix will also cause users to think, ‘my phone is slow so I should replace it’ not, ‘my phone is slow so I should replace its battery,” he added.
In October, researchers found that the initial release of iOS 11 drained iPhone batteries more than twice as fast as the previous operating system iOS 10 did.