The latest WhatsApp Beta (version 2.20.13) finally brings the long awaited dark mode. To activate download here, install and head to the three dots in the upper right corner. Next select Settings > Chats > Theme > Dark. FYI, going from stable to beta doesn't affect your chats or settings in anyway.
Facebook wants to unify the underlying messaging infrastructure of WhatsApp, Instagram and Messenger
The latest version of WhatsApp introduces a shortcut for group video and voice calls. Now in the top right corner of any group you will see a phone with a plus sign next to it. Pressing this button will allow you to select which members to group call.