Some of us carry around multiple phones for a variety of reasons. Syncing up your mail and some instant messengers across multiple devices usually isn’t an issue, but it is a feature that is lacking in WhatsApp because your account is tied to your phone number.
The good news is that according to WABetaInfo, it appears that WhatsApp is working on allowing that. The report claims that in the latest beta of WhatsApp, the company is testing out a new feature that lets users link another mobile device to their WhatsApp account. This means that users will be able to use their main WhatsApp account across multiple devices.
Messages from the original device can be synced to the secondary one, which means that chat history can be copied across devices. At the moment, WhatsApp already allows for multiple devices like your smartphone and computer, but not smartphone to smartphone, so this could be useful for users who have multiple mobile devices.
We’re not sure if the syncing of chat history can be done across platforms, like iOS to Android and vice versa, and if that chat history can then be synced back to the original device. WhatsApp recently expanded its native chat history migration to more beta users, so perhaps this could be a possible feature.
Either way, it looks like the feature is still in early development so it could be a while before we see it roll out to the public.
Source: WABetaInfo