WhatsApp app in Windows Phone Store just got updated to v2.11.306. This is a minor release with no new features, instead it got bug fixes to make the overall experience better. It seems the developers behind WhatsApp have realized the momentum behind Windows Phone platform, as they are actively pushing out updates every other week.
Currently, WhatsApp is limited in Windows Phone platform due to few platform restrictions. One of the most requested feature in the WhatsApp for Windows Phone is the ability to send music/video from the local phone library and the ability to save received music/video to the local phone library. If Microsoft can fix these in next Windows Phone release, WhatsApp should be able to include the requested feature too.
You can download the update in the Windows Phone Store here.