iFixit

If you think your older iPhone seems to run more slowly, you're not crazy.

Apple on Wednesday said a software feature released last year makes your phone operate more slowly to offset problems with its aging lithium ion battery. As batteries get older, they don't hold their charges as well as newer batteries, and can have worse problems when the charge is low or the temperature is cold.

The aging battery means your phone could have trouble operating or might unexpectedly shut down, as happened to the iPhone 6 and 6S last year. The processors in those devices wanted to hit faster speeds, but their batteries couldn't handle the demand, prompting some phones to simply switch themselves off.

To address that, Apple's iOS software, starting with last year's iOS 10.2.1, incorporated better power management capabilities, the company says. The operating system slows down your device to prevent it from shutting down, Apple says, but only in cases of cold temperature, a low battery charge or very old batteries.

Instead of your processor completing a task immediately, it will spread that out over more attempts to help manage the power consumption.

Now playing: Watch this: Yep, Apple slows down older iPhones

You may be wondering why we can't simply get better batteries. So do consumer electronics companies, which have thrown millions of dollars at the problem, with very little to show for it. An advanced battery startup in California, Envia Systems, a few years ago did some research and found that it took more than a decade, from 1995 to 2007, to double the energy stored in a battery -- and since then it hasn't even risen by 30 percent.

Meanwhile, smartphone users continue to look for ways to set things right when their batteries start wheezing and sputtering. Over on Reddit, for instance, the discussion has turned to whether it makes sense to replace an iPhone battery, how to do so and what the consequences might be.

Apple's software from last year applied to the iPhone 6 and 6 Plus, 6S and 6S Plus and SE. This year's iOS 11.2 extended the feature to the iPhone 7 and 7 Plus. It will be applied to other Apple devices in the future.

Apple said in a statement:

"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices. Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components. Last year we released a feature for iPhone 6, iPhone 6s and iPhone SE to smooth out the instantaneous peaks only when needed to prevent the device from unexpectedly shutting down during these conditions. We've now extended that feature to iPhone 7 with iOS 11.2, and plan to add support for other products in the future."

The statement from Apple came in response to a report earlier this week from Primate Labs, the company behind the Geekbench processor benchmarking software. John Poole, founder of the organization, said in a blog post that processors in iPhones slow down and decrease in performance as batteries age and lose capacity. Poole explained that users expect their phones to perform the same regardless of how old the battery is, but his tests indicated that wasn't the case.

iPhone users have long complained their devices seem to slow down when new models are released. Some have said they believe it to be a purposeful effort by Apple (and other tech companies) to hamper the performance in order to get users to buy new models. Apple has long denied this assertion.

iPhone battery angst

Still, its lack of transparency about making iPhones run slower caused backlash online.

"Apple should have been more transparent with end users, the press and analysts," Moor Insights & Strategy analyst Pat Moorhead said.

And Marco Arment, an iOS developer who co-founded Tumblr, tweeted that "the reputation damage from secretly slowing down old iPhones, regardless of the reason, will likely linger for a decade."

Many people called for Apple to notify users when it started throttling their phones' performance, as well as give them a setting to decide whether to allow that slowdown or not.

Ban Bajarin, an analyst with Creative Strategies, said Apple should give users the option.

"The battery life issue for Apple, and iPhones, is a fascinating one because the average life of an iPhone is so much longer than other devices," he tweeted. "It is their attempt to problem solve for lots of people who hold onto phones for [three] years or longer."

CNET

Apple didn't comment on whether a new iOS release would add notifications or an option to turn off the slowing feature.

For some people, the solution to a slower, older iPhone may be to update the battery instead of purchasing a brand-new device. Apple charges $79 to replace the battery of an iPhone that's no longer covered by a warranty. You also can buy a kit online to replace the battery yourself, something that's not exactly easy.

Apple has faced criticism about how difficult it is to replace iPhone batteries. Many older Android phones had removable backs that allowed users to swap out their batteries (though using new materials like metals has caused some, like Samsung, to stop offering that sort of phone design). For an iPhone, though, changing a battery has long been a tough task. An iFixit guide on replacing the iPhone 6 battery involves 25 steps. The screws to take the device apart are tiny, and making a mistake can cause you to brick the phone.

If you opt to replace your iPhone battery, the feature that slows down the phone will automatically turn off. You'll no longer see your iPhone performance slow -- at least not until that battery gets old, too.

Originally published Dec. 20 at 1:19 p.m. PT.

Updated Dec. 21 at 7:36 a.m. PT: Added background about battery technology and steps users could take.

Updated Dec. 21 at 8:40 a.m. PT: Added analyst comments and information about replacing an iPhone battery.

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