Last seen itself is a feature that hides when someone opens the WhatsApp application. This feature works by showing the last hour time the username performs an activity on WhatsApp. We can see the last hour of our contact list doing activities on WhatsApp. We can see under the username on the chat tab.
For now the feature in last seen can only hide based on a few choices everyone your contact and nobody. Based on screenshots of the WA beta intro there will be a my contact except option which means we can choose some contacts that can see our last activity.
With the last seen feature update on WhatsApp. Users can exclude certain contacts from being able to see their status. So only the closest people can see the user's online status. As you know, it goes both ways. This means that if we turn it off then we also can't see the last online status of the contact we turned off the feature.
Although this new update is seen running on the iOS operating system on screenshots shared by the WhatsApp beta. But there is no definite information when it will be widely released on users both on Android and on iOS.
The latest feature of Last seen that can choose your contacts Is very useful for those who want to hide their online status. Moreover, some contacts in the more we certainly have people who are not how familiar we know. It's useful to maintain privacy.