EE, the phone network that likes to be first with new stuff, has today announced "Enhanced HD Voice", which, as the name suggests, is voice calling enhanced with HD.
It'll be available first to customers using an iPhone 8 or iPhone 8 Plus, but it will become available to more handsets over the next few months. Enhanced HD Voice will take effect when using either a 4G signal or wifi calling, giving you superior sound quality and improving the reliability of voice calls.
However, you'll only benefit from the service if the person you're calling is also an Enhanced HD Voice user. So at the minute, you'll need to have an iPhone 8 and be calling someone with an iPhone 8 to benefit. Since the handset has only launched today, most of us will have to wait a while to experience the wonder of a HD phone call.