Strict Account Settings is a "lockdown-style" mode that builds on the platform's existing end-to-end encryption, adding stronger privacy features and additional restrictions against unknown contacts. For most WhatsApp users, this level of lockdown is overkill. As noted, the new WhatsApp settings are similar to Apple's Lockdown Mode, an OS-level feature that blocks attachments, link previews, and communication from unknown contacts alongside some other settings changes. Two-step verification and security notifications, which alert you if a contact's security code changes, are turned on. How to enable Strict Account Settings on WhatsAppThese controls can be enabled by going to Settings > Privacy > Advanced and toggling on Strict account settings.