This information was forwarded to me from a friend of a friend who is a police officer who was notified at work:
The latest WhatsApp update has automatically changed/made your groups open to everybody by default, so that people you don't know can add you to a group without your knowing. These people may include scammers, loan sharks etc.
You can change its default settings as follows:
1. Go to WhatsApp.
2. Settings.
3. Account.
4. Privacy.
5 .Groups.
6. Change from 'Everybody' to 'My Contacts'
William and Catherine’s Anniversary Photo
