If you are downloading WhatsApp APK on a regular basis, then you will know that the app is releasing new versions almost every day, where there are even times when more than one build are released, though they are mostly beta versions that contain the usual bug fixes sans any major features and changes.
Recently, WhatsApp has released its new version number 2.16.179 with build number 451272, which weighs 26.51 MB and works on Android 2.3.4 and later versions. Take note that WhatsApp recently increased its minimum requirements on Android from OS 2.1 to 2.3.4. Since the WhatsApp 2.16.178 update, there are no new features nor visual changes coming with this update, which means that you can expect from it only improvements and bug fixes, enhancing the stability and speed of the app.
Now, you will be surprised to know that there is already another version of WhatsApp for your Android tablet or smartphone, which is the version number 2.16.183, with build number 451276. This weighs 26.43 MB and is compatible with devices that run on Android 2.3.4 or later.
As you can see, WhatsApp is already supporting the OS 2.3.4+, from just the OS 2.1+. Also a beta version, the v2.16.183 APK comes with improvements and bug fixes, which means that you cannot expect any major visual changes.
You can get the latest version of WhatsApp on your Android device through the beta program on the Google Play Store. Other than this, you should know that, as a beta release, it can be downloaded by registering to the beta program in the Google Play Store.