For several months, WhatsApp has been testing a feature that would allow users to link their account to secondary devices and continue to send and receive messages without the primary smartphone online. This feature is now officially rolling out to all WhatsApp users in the most recent update of WhatsApp on both Android and iOS versions.
Previous Version for Beta Users
Previously, you had to make sure your main smartphone was still connected to the internet before you could carry a conversation on your linked web browser.
When enabling this feature on your smartphone, you need to opt into the feature - labeled as still in "Beta". Once enabled, you'll be unlinked from all devices before re-linking to a new device. Once linked, it behaves pretty much the same way, except you'll be able to chat regardless of whether your main smartphone is online or not. Plus, messages and calls are still end-to-end encrypted.
New Version for Beta Users
Now, linked devices will be able to receive and send messages up to 14 days after the main smartphone goes offline. This might be useful if you're in a situation where you've lost your smartphone temporarily and needed to stay in touch with folks through WhatsApp, or if you smartphone runs out of battery but you're near a linked computer.
Limitations
Sadly, there's a limitation on iOS that doesn't allow you to delete messages or conversation threads from a linked device. The other limitation is that you still cannot link a tablet or secondary smartphone.
To check out the feature, update to the latest version of WhatsApp and tap the three-dot menu. Then tap "Linked devices" and enable the feature
