A warning has been issued to MILLIONS of WhatsApp users. It comes as WhatsApp faces a big change in settings from today (Thursday) onwards.

WhatsApp is rolling out Disappearing Messages from today. This allows messages to be deleted after a certain allocated amount of time.

If the feature of Disappearing Messages on WhatsApp is enabled, then your messages would automatically be deleted after seven days. You can simply turn on/off the WhatsApp disappearing messages for individual chats, but only admins can enable/disable it for group chats.

Even if you have not opened the chat, the WhatsApp messages would be disappeared after 7 days (but you can view them on the notification bar). If you have quoted the message, then you can access it even after 7 days.

WhatsApp warns: "Only use disappearing messages with trusted individuals. For example, it's possible for someone to: Forward or take a screenshot of a disappearing message and save it before it disappears, Copy and save content from the disappearing message before it disappears and Take a photo of a disappearing message with a camera or other device before it disappears."

You can turn on disappearing messages by default for all new individual chats. If on iPhone and Android, go to WhatsApp Settings > tap Account > Privacy > Default message timer and select a duration.