WhatsApp does not support access to a single account from multiple devices. WhatsApp is a very private messaging app from Facebook and the information shared via this app is end-to-end encrypted which means no one except you and the intended recipients can access the information remotely. A single account on this app can only be accessed from one device at a particular time. But WhatsApp Web allows users to open the same account from your website after scanning a QR code, and for this, you have to keep your WhatsApp on your smartphone.
A recent tweet from WABetaInfo shows an image that comes with a caption that mentions a single WhatsApp account can be accessed from 4 different devices at the same. This tweet also mentions that this process is under development. So, from this, we can assume that WhatsApp is going to take a loose on the limitation of devices this time allowing it up to four devices at the same time. Here devices refer to smartphones and can be accessed from it without using the WhatsApp Web feature.
Now coming to the image, we can see that it mentions “Connected to WiFi” and “Tap “Continue” to begin the login process”, this clearly mentions that the app would use Wi-Fi connectivity to sync data across devices. It can also happen that all the devices would have to be connected in the same WiFi network to access the account and sync its data.
Whatever the final product be if WhatsApp makes this move a lot of users will be pleased. A lot of users were demanding this feature for a long time. Moreover, WABetaInfo has also mentioned that this feature is under development so this means that it is not in any parts of the recent Beta updates. Hence, WhatsApp may also apply some changes in the final version of this feature update before making it public.