When customers who have their Touch ID fingerprint sensor/ Home button replaced by a third party (not by Apple, that is) update their iPhone to iOS 9 or beyond, Error 53 occurs.

Some customers say they haven't even replaced their button by a third party, but just damaged the button a little or dislodged it a bit, Mac World UK reports.

In fact, some are even saying that they've seen Error 53 after simply getting their screen replaced and not the Touch ID.

As users know, screen replacement is a very common repair that customers use third parties to carry out.

These customers see the Error 53 code in iTunes after they have done an update.

The bad news for these users is that there is no return. Error 53 completely blocks your phone, rendering it unusable and completely useless. What's more, it also makes any photos or data you have inaccessible to you - even if you refer it to Apple.

The phones that are known so far to be affected by the Error 53 are the iPhone 6, iPhone 6 Plus and iPads with Touch ID. The iPhone 5s isn't affected. Confirmation is still being awaited for the status of Apple's iPhone 6s and iPhone 6s Plus being affected.

Apple claims that Error 53 is for the sake of users' security. Since Touch ID is a fingerprint sensor whose function is to help keep an iPhone secure and to allow secure mobile payments to be made, Apple's detection of an unauthorized Touch ID sensor installation on an iPhone makes the phone automatically consider the iPhone unsafe and basically kill it.

According to Apple, this measure of security is vital for the protection of the iPhone and prevents fraudulent Touch ID sensor from being used.

Error 53 is a hot topic at present is because it has been featured in the media recently, including in news about a class action lawsuit by PCVA against Apple for Error 53. There has been speculation that Error 53 might be a ploy by Apple to increase revenue. This is because Error 53 essentially prevents third party repairs - and Apple's repairs can be costly.

There is also talk about how this might be illegal under the Criminal Damage Act 1971, which declares intentionally destroying someone else's property to be an offence

For customers worried about avoiding this error: there are ways, if not permanent solutions (yet) to avoid it. The best policy would be to not have your Touch ID fingerprint sensor replaced. And if you already have, the error can still be avoided as long as you don't install a system update or restore your device from a backup.