Apple has admitted to intentionally slowing down iPhones as they get older, without notifying customers.

The revelation would appear to lend weight to a popular conspiracy theory about the mobile phone.

However, the tech giant claims the move is not designed to encourage customers to upgrade to newer iPhone models.

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Rather, Apple says it throttles iPhone performance as a precautionary measure. If it did not, the company claims, older iPhones would keep shutting down unexpectedly or break earlier than they should.

“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,” Apple told Reuters.

“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 issue comes from the iPhone’s battery, rather than its processor.

How to improve your phone's battery life Show all 9 1 /9 How to improve your phone's battery life How to improve your phone's battery life Limit notifications Notifications are incredibly useful, but they also drain battery life and not all of them are actually necessary. Switching off notifications for certain apps can help your phone’s stamina. On Android, head into Settings, hit Apps and select those you don’t need to be notified by. On iOS, go to Settings and then Notifications. How to improve your phone's battery life Disable auto-sync Certain apps, such as email and social networks, constantly run in the background even when you’re not using them. This is so you see updated information and updates when you do open the apps, but the benefits can be offset by the amount of battery life auto-sync can eat up. On Android, you can turn off auto-sync by going to Settings, Accounts and hitting the menu button. On iOS, go to Settings, General and Background App Refresh. However, since auto-sync is genuinely useful, we’d recommend disabling it when you know you’re going to be running low on battery life, rather than switching it off all the time. How to improve your phone's battery life Switch off location services GPS is a huge drain on your phone’s battery, as more and more apps use your location data to work out where you are, and shape your experience according to that information. Unless you’re using a Maps app, you can get by without it. To turn off GPS on Android, go to Settings and Location. On iOS, go to Settings, Privacy and Location Services. How to improve your phone's battery life Lower brightness Your phone’s display is responsible for the biggest impact on your battery life, but it’s easy to limit how much energy it uses up. Auto-brightness is convenient, but often sets the screen brightness to a much higher level than it needs to be. Turning auto-brightness off, setting your display’s brightness to a lower level and adjusting it when you need to is much more sensible. How to improve your phone's battery life Uninstall apps you don’t need Some apps drain more battery life than others, and it’s worth working out which ones you can do without. Facebook, for instance, is known to have a big impact on your phone’s battery, and you can eliminate this by deleting the app and using the social network in your web browser instead. On Android and iOS, you can see the apps and processes that are affecting your battery by going to Settings and Battery. From there, work out what you can delete or replace with a less-demanding alternative. How to improve your phone's battery life Cut your assistant off Virtual assistants are becoming increasingly capable, and therefore increasingly important in tech companies’ eyes. Not all consumers share the enthusiasm of Google and Apple though, and rarely - if ever - use Google Assistant and Siri. Whether you use them or not, by default the two assistants are always listening out for their trigger words, and this uses up battery life. On Android, you can switch this off by going to Settings, Google, Search, Voice and “Ok Google” detection. On iOS, go to Settings, Siri and Allow “Hey Siri”. How to improve your phone's battery life Stop vibrating Vibrate is a great middle-ground between a potentially disruptive ringtone and total, uncertain silence, but it also uses up the most battery life of the three options. You can go a step further by also disabling tap feedback, which can be reassuring, but is ultimately unnecessary. How to improve your phone's battery life Turn off connections If you’re connected to a Wi-Fi network, switch your mobile data off, and vice versa. Similarly, remember to turn off Bluetooth and NFC when you’re not using them. How to improve your phone's battery life Airplane mode Airplane mode isn’t just for when you’re on an aeroplane. If you know you’re not going to have or won’t need signal or a Wi-Fi connection for a good amount of time, it’s worth enabling Airplane mode. Otherwise, your phone will use up battery life by pointlessly trying to connect to a network.

iPhones use lithium-ion batteries, which degrade over time, and Apple says that if it did not throttle performance there would be a greater risk of internal components being damaged.

Customers have long suspected Apple slows iPhones down as they age, but this is the first time the company has admitted to doing so.

It addressed the issue after Primate labs founder John Poole analysed iPhone 6S and iPhone 7 performance over time.

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“Users expect either full performance, or reduced performance with a notification that their phone is in low-power mode,” he wrote in a blog post earlier this week.

“This fix creates a third, unexpected state. While this state is created to mask a deficiency in battery power, users may believe that the slow down is due to CPU performance, instead of battery performance, which is triggering an Apple introduced CPU slow-down.