Although WhatsApp gives you the option to hide your Last Seen, your friends can still see when you're online. A long-requested feature that might soon be implemented is the option to hide the online status which is the last privacy setting users would need.
You may be able to hide your online status from everyone in WhatsApp's most recent beta version, according to WABetaInfo. This is perfect if you're being stalked on WhatsApp and don't want your relatives or friends bothering you as soon as they notice you are available.
You will have two options while using the new feature. You have the option of making your online status public if you want it to function like Last Seen. This implies that you have the option of letting everyone see your online status, just your contacts, just your contacts with a few exceptions, or nobody at all.
Although the screenshot is of iOS, according to WABetaInfo, WhatsApp is also working on bringing the feature to Android and WhatsApp Desktop as well. It is unknown as to when the functionality will get live because it is currently in the beta testing. As soon as new details are available, we'll update you all.