WhatsApp is testing multi-device authentication, which shall allow users to sign-in from the same account on multiple devices. Currently, user can authenticate single device by means of mobile number verification. As soon as you change the device and sign-in on another device, WhatsApp automatically logs you out from all other devices. The multi-device sign-in feature, which is currently tested internally by WhatsApp, would allow users to sign-in on the same account from different devices.
“From now on WhatsApp is internally starting some important tests for the multi device feature. It’s not available yet and there isn’t a release date: it could be next two months, four months, six months… but it’s really positive that they have started to test it on the whole” wrote WABetaInfo on Twitter.
The multi-device sign-in feature would allow users to use single WhatsApp account on multiple devices simultaneously. Therefore, it would be easier to switch from a mobile phone to tablet or iPad, and computer and continue the conversation from where you left on the last used device.
Though the details are scarce, the multi-device feature might also allow users to transfer data from Android to iOS device in real time. Currently, you can move WhatsApp to iOS device from Android device but there is no provision to transfer chats and other WhatsApp data on iOS from Android, or from iOS to Android. The multi-device sign-in might bring a sync and let user sync data across devices.