Apple faces class-action lawsuit over iPhone software update

Some iPhone users who were unhappy with the latest software upgrade have filed a class-action lawsuit against Apple.

According to the lawsuit, the tech giant's iOS 9 software update made iPhone 4s phones slow, buggy and subject to crashes.

Apple promoted iOS 9 as being compatible with the iPhone 4s, making the phones faster and more responsive.

The suit is seeking $5 million in damages.

Apple has not commented.