After the significant update last week, WhatsApp for Windows Phone devices just received another update in Store. This v2.12.180 update seems to be a minor update with just bug fixes and improvements.
Previous update change log:
• Improved search lets you instantly find messages, chats, and contacts. This may take a few days to show up after you update the app.
• Support for in-app notification sounds
The update can be found at the link below.