WhatsApp's new version 184.108.40.206 has been updated through the Google Play Beta Program. The new version is still under development. The two main features that will make an appearance in version 220.127.116.11 are join missed calls and biometric lock.
Join missed calls is a new addition to the group calls, which will allow users to join a missed group call any time they open WhatsApp while the call is still on.
The biometric lock on the other hand has been added to protect WhatsApp via fingerprint and support more ways to authenticate user identity to open WhatsApp. Fingerprint lock, however, will not work for those Android users whose devices have a face recognition system.