Currently available to beta testers
If you constantly chat with a lot of people on WhatsApp, sooner or later your chats can become a mess: some new messages will get lost. It turned out that the messenger is working on a function that will allow you to understand this.
WhatsApp has reportedly released a beta version of the app for iOS and Android with the ability to filter messages by “Unread”. This useful feature has appeared in WhatsApp business accounts since January. It looks like the messenger is now working on making it part of the service for all accounts.

The screenshot above shows what it will look like. The filter button is located next to the search bar. When you click on it, the application will automatically change the way it displays a list of all your chats, making it easier to detect unread messages. Also, if the filter is enabled and you use the search bar, WhatsApp will only display unread messages as results.
More beta testers will get this feature in the coming weeks. After the testing process is completed, the option will appear for all users.