It seems that more and more interesting features on mobile devices will be limited to Europe only. App sideloading on iOS and third-party app warehouse support will not be offered outside of Europe. Recently the cross-platform messaging feature on WhatsApp will also be limited in Europe only.
In the new update, WABetaInfo discovered a brand new Third-party chats feature. Users are seen to be able to turn this feature on or off according to their own taste and can also choose which messaging service to include in WhatsApp. WhatsApp also reminds users that third-party messaging may use different encryption and users are more susceptible to scams and spam.
Based on this leaked screenshot it can now be assumed that the cross-platform messaging feature on WhatsApp is like Beeper. Users need to connect their respective accounts and then can read, receive and send messages from various different platforms in one application.