According to the announcement post, this will allow you to use WhatsApp on up to four other devices simultaneously. Each of these devices will connect to WhatsApp independently, meaning you don’t need your phone to be nearby once the other devices are connected to the service. End-to-end encryption, one of the key draws of the app, will be maintained across all the connected devices.
Achieving this is basically to not have the phone be the “source of truth” from which other connected devices mirror content. As it works right now, the phone holds the identity key for your WhatsApp account. This new method gives each device its own identity key.
This new multi-device capability of WhatsApp is still in its limited public beta though. The post also does not detail when it will be available for the rest of its user base. If you’re feeling adventurous, you can sign up for the beta by tapping on the kebab icon, followed by Linked Devices, Multi-device beta, and JOIN BETA. Though at the time of writing, this option was not available to us. (Source: WhatsApp [1], [2])
