WhatsApp True Multi-Device Support Arrives, But Only For Some Users
Facebook has improved WhatsApp multi-device support and it is making it available to some users as a limited public beta test. With this beta, WhatsApp users can finally access their chats across multiple devices other than their smartphone — and these devices won't be dependent on your phone to continue using the messaging service.
The key aspect of this improved multi-device support is that users aren't required to have their phone up and running nor connected to the Internet. Users have the option of connecting their WhatsApp account to up to four non-phone devices in addition to their smartphone, meaning you can, for example, access it on your tablet and laptop, too.
Each device added to your account will connect independently so you can continue chatting even if your phone dies. Despite the change, Facebook says that each device will have the same end-to-end encryption and privacy features you get from the mobile app. This is made possible by "new technologies" Facebook says it has developed to sync users' data between devices while still offering end-to-end encryption support.
The syncing includes chat archives, starred messages, contacts, and other expected content. This is made possible by giving each device its own identity key and mapping them in the user's account, forming a collection of device identities between which the user's content is synced. Users have the ability to verify their contact's devices to make sure they're sending messages to the person they intend.
Facebook says it has also taken other steps to prevent malicious actors from quietly adding devices to a user's account in order to eavesdrop on messages. Automatic Device Verification will play a big role in this by "automatically establishing trust between each other" so that users won't need to verify identities every time a contact adds a device to their account.
Facebook details the tech behind its true multi-device support in a post on its engineering blog. The company says it is testing this new option with only a small group of users at this time, ones who are already participating in the company's beta program. More people will get access to the support in the future, including new features Facebook says it plans to add to the support.