One of them is 2 factor authentication. Usually when you register a WhatsApp account you are sent a code to activate it via SMS. With 2 factor authentication, your email address will also need to be linked to your account. This will further strengthen the security of your account with nobody being able to use your number for WhatsApp without your knowledge (by stealing the code).
How to Enable 2-step VerificationHere’s how it works, first you need to go to settings and then in account settings. You will see the two step verification option there.
Once you tap on it you will be prompted to enable 2 step verification. After that you will be sent a 6 digit passcode which you will need to enter in the next step.
You will then be asked to enter your email address to complete the 2 step verification setup.
When completed successfully you will be shown this message.
Now whenever you change your phone and need to activate WhatsApp on your number again, 2 step verification will ask you your email address and will send you the pass code on it.
Play Audio messages in BackgroundAnother new feature added to the recent beta versions of WhatsApp is the ability to play audio messages in the background. You had to stay within the conversation or group the audio message was in to listen to it. Now you can switch conversations and even switch apps while listening to audio messages. However if the screen turns off the message will stop playing.
Take note that these two features are available on the beta version for now. Beta versions are liable to contain bugs and glitches and should not be used as your default app. If you know the risks and are still willing to use it, you can download the APK from APK Mirror.
Via Android Police