WhatsApp multi-device support rolls out to beta users

It’s almost here. Long-awaited multi-device support from WhatsApp has landed as an experimental feature. The Facebook development team announced this this week and explained the complex inner workings of the function.

According to Facebook, the support of multiple devices has led to a “rethinking” of the architecture of the chat app.

This is how multi-device support works

Previously, WhatsApp viewed the primary smartphone as the “source of truth” – the device used as the cornerstone of account encryption for these users. As a result, this device had to be available at all times, even when companion devices such as a PC connected to WhatsApp Web were used.

Now Facebook has redesigned this system. WhatsApp’s new architecture ensures that companion devices can act independently while maintaining synchronization with the primary smartphone whenever possible.

“WhatsApp Multi-Device uses a client fanout approach in which the WhatsApp client sending the message encrypts it N times and transmits it to N different devices – those in the device lists of the sender and the recipient,” explains this Facebook engineering team.

This design allows users to send messages or make calls from companion devices even when their primary smartphone is turned off or disconnected.

This arrangement allows WhatsApp to synchronize app data and message history across devices without having to rely on a central server. However, the company stores “a copy of each application state that can be accessed by all devices” on a server for redundancy reasons. The company states that this data is “end-to-end encrypted with ever-changing keys known only to that person’s devices.”

What’s not included

Annoyingly, users are allowed to have up to four companion devices on their account, but none can be smartphones. This makes the feature a lame duck for those who want to use a single WhatsApp account on two smartphones.

The beta also lacks key features. Initially, you will not be able to view another user’s live location on companion devices, nor will you be able to call others from a companion device if they have an outdated version of WhatsApp installed. The processing of group invitations is also limited to the primary smartphone for the time being. There are also limited functionality for Portal, WhatsApp Desktop, and WhatsApp Business users.

How to enable the beta version of WhatsApp for multiple devices

If you’re already on WhatsApp’s beta channel, update your app. After that, you can check if the feature registration option is available on your device. In order to do this:

• Open WhatsApp.
• Tap the More options Menu – the three button menu in the upper right corner.
• Tap Linked devices.
• Choose Multi-device beta.
• Tap Join Beta.

The multi-device beta option is only visible if the feature is available to you. Even though I’m getting WhatsApp beta builds, the feature wasn’t available on my device.

If you want to get out of beta, you can too. Follow the same steps as above but tap Exit beta instead in the last step.

WhatsApp hasn’t announced when multi-device support is expected to hit stable builds. We imagine that the company still has a few bugs to fix and functions to improve. Still, after months of rumors and teasers of the beta rollout, the initial feeling is that multi-device support is almost primetime ready.