Apple has admitted that it was purposefully slowing down older iPhones to save battery life - even on handsets that were barely three years old.
This intentional slowdown of older iPhones (particularly the iPhone 6 and 6s) began with iOS 10.2.1, which “dynamically manages the maximum performance of some system components” to reduce the instances of random battery shutdowns on older phones - in other words, sacrificing power and performance for longer battery life.
As the iPhone"s lithium-ion battery gets older it will start to need charging more frequently, and may even start to shut down your phone unexpectedly.
Of course the same is true for all rechargeable batteries in any smartphone, computer or other device - whether made by Apple or not.
Apple suggest you replace your iPhone’s battery once it has passed 500 complete charges. Annoyingly iOS doesn"t actually tell you how many charges your iPhone has been through, but you can find out whether the battery needs replacing in Settings - read our How to check if the battery in your iPhone may need to be replaced for full details.
Apple has now apologised for not being more open about its iPhone slowdown strategy, and makes a generous offer to iPhone customers.
How much will Apple iPhone battery replacement cost in the UK?
In a sign of real contrition (helped by the threat of class-action lawsuits from angry customers and hungry lawyers) Apple is giving all users with an iPhone 6 or later the option of replacing its battery for just US$29 - down from the usual $79 out-of-warranty replacement price.
No UK price has yet been given for the Apple iPhone battery replacement program, but, as the cost of replacing the iPhone battery is £79, we can expect a UK Apple iPhone battery replacement fee of £29.
If Apple needs to ship the repaired iPhone to you it will add a shipping fee of £7.44.
If your iPhone is still under warranty then there is no fee for battery replacement. The Apple Limited Warranty covers against manufacturing defects for one year from the date you bought them. It doesn"t cover damage caused by accidents or unauthorized modifications.
With a new battery the iOS operating system will no longer need to conserve power. As Apple says a replacement battery will return iPhone performance to normal, this official Apple battery replacement will be like getting a new iPhone for £30/$30 - with all the scratches you"ve lovingly added over time, of course.
How long will iPhone battery replacement take?
If you send your affected iPhone to Apple it should take approximately 6-8 days for the battery replacement to be taken care of.
This time is reduced to up to 5 days if you take the phone to an Apple Authorized Service Provider (AASP).
Strangely Apple suggests it can take up to 6 days if you take the affected iPhone to an Apple Store appointment, but the company does state that same-day repair options maybe available at Apple Store and AASPs.
Apple may be able to offer you a loan iPhone while yours is off for repair, but only for those still under warranty - so unlikely for this battery replacement program: "If you bring your iPhone to an Apple Store or an Apple Authorized Service Provider, we"ll try to fix it during your appointment. Some iPhone repairs require precise calibration on specialized equipment. If we need to send your iPhone to an Apple Repair Center, we"ll check to see if you can use a loaner while your iPhone gets repaired. A loaner iPhone is available for most repairs that are covered under the Apple Limited Warranty."
Other battery saving tips
We"ve got nearly 40 tips for how to improve iPhone & iPad battery life, which is certainly worth reading.
We also recommend considering a battery case for your iPhone, which will extend the daily usage you can get from your phone and also protect it from everyday bangs and knocks. Read our round up of the best iPhone battery cases for some recommendations.