Looking to improve the calling functions on iOS devices, Apple on Monday announced iOS 10 features like voicemail transcriptions, and a new API for third-party VoIP apps, allowing them to behave more like regular iPhone calls.

The transcription function will try to interpret what a caller says in text form, sometimes eliminating the need to play back a message. These transcriptions can also appear in iOS 10's improved notifications, saving the trouble of even unlocking a device.

The new VoIP API will firstly allow third-party apps like WhatsApp to display incoming calls on the lockscreen as if there were from Apple's own Phone app, including standard "Remind Me" and "Message" options. Third-party apps can appear on a person's iOS contact page.

Apple has meanwhile collaborated with Cisco, enabling calls to a work VoIP number to reach a personal phone.

Finally, where supported, iOS 10 will try to gauge whether an incoming phone call is spam, displaying an alert while it's still ringing.