As it is now, VoIP features on such apps can run in the background when not in use, allowing them to connect calls faster. According to The Information, messaging apps like WhatsApp also use VoIP in other ways. One of this is implementing end-to-end encryption. But because they run in the background, this also allows them to do other things like collect data.
In the future, Apple will only allow background access to be used for VoIP calls, and nothing else. The restriction will mean that messaging apps developers will have to find another way to implement end-to-end encryptions. This will be hitting Facebook a little harder than others as it has the feature a number of apps, including Facebook Messenger. For what it’s worth, Facebook claims that it never used the API for collecting data. A company spokesperson told the Information “we are using the PushKit VoIP API to deliver a world-class, private messaging experience, not for the purpose of collecting data.” (Source: The Information via The Verge)
