Contacts I have chats with" will only notify people the user has had chats with. "You can also choose to notify contacts who you have a chat with", the report said. To start using the feature, click on Settings Account Change number.
It should be noted that blocked WhatsApp contacts won't be told about the new number. Folks at the publication who got their hands on the app discovered that it was possible to find out if a WhatsApp user is online or not simply by initiating a conversation with them, where no messages need to be exchanged for this to work.
We all use WhatsApp, more than we use the smartphone for anything else.