A new (stable) version of WhatsApp Messenger has just been released (Nov. 14, 2015) and is compatible with all Android devices running Éclair (2.1) or higher. This particular update, WhatsApp 2.12.358 APK, doesn’t have any noticeable changes unless you’ve been having issues with an older version of WhatsApp. If that’s the case, then you will most likely find that the bugs you’ve been dealing with have been fixes and the app runs smoother and faster in general. It’s always advisable to keep your apps updated in case of any important security fixes (unless you’re having specific issues with a new version, but that’s another story).