Apple FINALLY reveals the cause of its iPhone 6s 'unexpected shutdown' bug - but only on its Chinese website

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Apple has finally revealed the details behind a technical glitch that saw some iPhone 6s handsets globally shutting down unexpectedly.

However, in a strange move by the firm, the explanation only appears to have been given to to users in China.   

Last month, Apple vowed to replace batteries on affected devices but remained silent on what exactly was causing the problem, though it stressed that it was not a safety issue. 

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Apple has finally revealed the details behind a technical glitch that saw some iPhone 6s handsets shutting down unexpectedly. It blames the fault on a battery component that was exposed to ambient air for longer than intended during the manufacturing process

'We found that a small number of iPhone 6s devices made in September and October 2015 contained a battery component that was exposed to controlled ambient air longer than it should have been before being assembled into battery packs,' reads a statement on Apple's Chinese website. 

'As a result, these batteries degrade faster than a normal battery and cause unexpected shutdowns to occur. 

'It's important to note, this is not a safety issue'. 

The company also pointed out that the unexpected shutdowns were designed to protect the hardware.

'We also want our customers to know that an iPhone is actually designed to shut down automatically under certain conditions, such as extremely cold temperature, said Apple. 

'To an iPhone user, some of those shutdowns might seem unexpected, but they are designed to protect the device’s electronics from low voltage'. 

The issue only affects a 'relatively small batch' of the devices manufactured last year, says Apple. The firm will not disclose the exact numbers. 

It is Apple's second iPhone repair program in less than a month after it announced that it will fix the 'touch disease' issue blighting many users' iPhone 6 Plus handsets.

Apple clarified that the iPhone 6s bug was not a safety issue and that it only affects devices within a limited serial number range

'Apple has determined that a very small number of iPhone 6s devices may unexpectedly shut down,' said the tech firm in an online statement. 

Apple clarified that the bug was not a safety issue and that it only affects devices within a limited serial number range, manufactured between September and October 2015.

'If you have experienced this issue, please visit an Apple Retail Store or an Apple Authorized Service Provider and have your device's serial number checked to confirm eligibility for a battery replacement, free of charge,' adds Apple.

To prepare handsets for the battery replacement, Apple advises users to back up their data to iTunes or iCloud, turn off the 'Find my iPhone' feature and then erase the phone to delete all content and settings. 

If the iPhone has any damage, such as a cracked screen, that impairs the replacement of the battery, then this will be need to be resolved first, says Apple, and there may be a fee attached.

The battery replacement itself is free of charge. 

For iPhone users who have previously paid to have their batteries replaced because of this issue, Apple is offering refunds.   

Apple said that it may limit the replacement scheme to the country where the handset was purchased. 

The unexpected shutdown issue doesn't appear to be limited to any specific region.

The battery replacement programme covers affected iPhone 6s batteries for 3 years after the first retail sale of the device. 

Last month, Apple also announced that it will fix the 'touch disease' issue blighting many users' iPhone 6 Plus handsets.

The issue causes the phone screens to gradually become unresponsive and a flickering grey bar to appear across the top.

When it was first reported several months ago, Apple appeared to be unequipped to offer repairs, but will now fix the issue - for a fee of $149 (£146.44 in the UK).

The service will be available to iPhone 6 Plus owners worldwide, however Apple said that it may limit the service to the country where the device was purchased. 

The repair scheme covers all affected iPhone 6 Plus handsets for five years after their first retail sale. 

FORGET JET BLACK: APPLE MAY SOON RELEASE A 'PURE WHITE' VERSION OF THE IPHONE 7 AND 7 PLUS

Apple's iPhone 7 sold out within minutes of pre-orders opening earlier this year, with the new jet black colour being the first to go.

But it seems the company might be considering another colour option for Apple fans.

Earlier this month, an Apple information website based in Japan said the company might have plans to bring out a 'pure white' or 'jet white'  version of the iPhone 7 and 7 Plus.

An Apple information website based in Japan said the company might have plans to bring out a 'pure white' or 'jet white' version of the iPhone 7 and 7 Plus. The website cited the source as a 'supplier'. Artist's impression of the white iPhone pictured

Sources speaking to Japanese publisher MacOtakara said a 'pure white' version of the iPhone 7 and iPhone 7 Plus could be brought out in the future.

'Apple seems to have a plan to add a pure white model to iPhone 7, iPhone 7 Plus,' the website said.

The website cited the source as a 'supplier'. 

'But this information may be unreliable,' the site added.

The company currently offers the iPhone 7 and 7 Plus in jet black, black, gold, rose gold and silver, while the Apple Watch is already available in a ceramic white.