A manufacturing fault has caused the on/off button on some iPhone 5 models to “stop working or to work intermittently.” Apple are addressing this problem by offering free repairs to anyone affected. The faulty models were manufactured in March 2013, so if you purchased an iPhone 5 after this period, it may be worth checking to see if your phone is a faulty model, even if it is currently working.
To find out if your iPhone is eligible to be repaired for free, you can check your serial number here on Apple’s website.
To find out your iPhones serial number, go to Settings on your iPhone, press on General and then About. Your serial number should be listed in this section. If you can’t find your serial number through this method, or you can’t turn your phone on due to a faulty button, there are other ways to find your serial number.
If you find that your iPhone is one of the faulty models, but have paid for this fault to be repaired in the past, you can contact Apple to receive a refund.