The WA report states that under WhatsApp multi-device support, users can use WhatsApp on four additional devices, so that users can run WhatsApp on five devices simultaneously. It has also been told in the screenshot that due to this feature, users may have some problem with performance and quality in the beginning, but gradually this problem will also be fixed.
The screenshot also shows that once the new multi-device feature arrives, users will need to install the latest version to use it. The report also states that the linked devices will work without an active internet connection on the main device.
WhatsApp has not yet confirmed when the multi-device will be available, but it is said that it could be launched very soon.