WhatsApp has introduced a new feature called “Companion Mode” for all beta testers on Android, which allows users to link their existing WhatsApp account to another mobile phone.
This feature is an extension of multi-device support and enables users to access their chats on a second device without requiring an active internet connection on their main phone. The chat history will also be synced across all linked devices.
However, some features such as managing broadcast lists and posting status updates from linked devices are still not available. This feature will allow users to use WhatsApp on up to four devices simultaneously.