With this tool you can find out what version number WhatsApp is currently in as well as whether you've got the most recent version installed. If you don't you can tap a link right there on the page to take you straight to Google Play.
From this tool's interface you can get all the details on the changes rolling out in all updates, big or small. Actualizaciones para WhatsApp shows a full list of all new features, tweaks, and changes that WhatsApp has added in its latest version.
Requires Android 4.0 or higher