Use WhatsApp on five devices soon: Beta testing begins for new feature

So far, WhatsApp can only be used on one main device, the smartphone. The messages are received there and are also encrypted and decrypted at this point. Anyone who wants to use the messenger on a tablet, Mac or PC, for example, must access the main device via a browser and the display of the user interface is merely mirrored.

All communication takes place via the smartphone and, by the way, also burdens its transmission quota, provided it is not logged into the WLAN. If the smartphone is not available for any reason, messages can no longer be sent via the mirrored companion devices.

WhatsApp has developed a new technology

In the future, up to four companion devices will be able to handle WhatsApp communication in addition to the main device. For this purpose, the developers have developed a new architecture where the security codes are enhanced and now take into account all device IDs of a user. This way, WhatsApp can verify the authenticity of a sender.

In a blog post, WhatsApp parent Facebook explains how the architecture is built and works. To make the system secure in that respect as well, and to prevent a third party from, for example, bringing in someone else's device as a companion device, you can specify that you also have to authenticate biometrically before the required QR code scan for device inclusion. WhatsApp users can also view which Companion Devices are registered to the account and when they were last in use at any time.

When a message is sent, the sender's app receives a list of the IDs of all the recipient's companion devices, encrypts the content - individually for each device - and then sends the package to all the recipient's devices. For synchronization, the message then goes to all sender devices as well.

If you later add another companion device to your account, the registered device combines the data from previous chats into one object and sends it encrypted to the new device.

How to become a WhatsApp beta tester

In order to participate in the closed beta, one must not only be an iPhone user, but also have the Testflight app installed and sign up for the test from there. Android users can gain access to the beta through a special page on the Play Store.

But be careful: The beta version can currently only communicate with other users of the same version.