The yet-to-be-announced feature has been spotted by WABetaInfo and comes after reporting about another experimental feature called ‘Newsletters’ that is meant to simplify group communication.

mute whatsapp spam calls
WaBetaInfo has posted a screenshot that shows the toggle to mute unknown calls and it can be found in the Settings menu of the app. When enabled, this feature will automatically block you from receiving calls from an unknown number. However, the calls will still be displayed in the call list and in the Notification Center. This will help you to know who called you.
Spam is nothing new on WhatsApp and it keeps coming back in many forms. There are many advertisements that serve as useful services. The instant messaging app was envisioned as a quick way to block spam messages. The new mute toggle is not visible in plain sight, although it has surfaced from recent Android beta platforms. It is not clear when WhatsApp will roll out the mute toggle but we can guess that public testing may start soon.
As far as the newsletter feature is concerned, one of its disadvantages is that it will always publicly display the phone number of the creator. This will allow any member of the WhatsApp community to contact you without your consent.