In the June 2019 iOS release, all calls from unknown numbers will be sent to an answering machine. The feature is called "Blocking unknown callers.
What do you need to do to protect yourself from the spammers who have been overpowered by cell phone calls lately? First, download the beta version of iOS 13 on the iPhone. After that, look for the "Phone" section in the smartphone settings. Then activate the item "Silencing unknown callers." After that, all subscribers who are not in your list of contacts will not be able to reach you. They will immediately be redirected to the answering machine or voicemail. You can listen to their messages later.
The new feature uses Siri to see if you know the person you're talking to. For example, if you communicate with a colleague only through e-mail, Siri will remember the person and mark the contact as familiar. According to this principle, it turns out that the user will be able to call the person with whom he is communicating now or communicated once.
Accordingly, no spammers or advertising numbers will be able to call you if the jamming function is enabled. This is very convenient: strangers will have to send a text message or write to messenger before calling.