Looks like Whatsapp Developers are working day night for their Windows phone app! They have pushed another update with change in location of Send Button and bug fixes.
The new update brings new UI closer to Windows 10 UI. The gray bar below the chats has been removed by developers.
Have a look at screen shots:
Well the latest BETA update will be available to Public App in few days or weeks. Whatsapp BETA is a private BETA testing app not available for users to download it from store. We will let you know when the latest update for Whatsapp is available!If you like our report please share your support by subscribing to our community on Facebook, Twitter, Telegram or Flipboard. you can also join our support group Smartphone Assistant for any queries related to your devices