WhatsApp started voice calling features, but this feature not enable just doing an update. It required some more steps that you need to follow. Follow these steps below to enable voice calling on WhatsApp for Android.
1. Click HERE to download latest version of WhatsApp for Android. The latest version on WhatsApp's website is 2.12.7, but if you are downloading from Google Play, ensure that your device has version 2.11.561. Older versions do not support this feature for all users.
2. After you have download and install latest version of WhatsApp on your Android phone, ask someone who has WhatsApp calling enabled to make a WhatsApp call to your number.
3. Giving a missed call does not work. You will have to receive the call and wait for a few seconds before disconnecting to activate WhatsApp voice calling.
4. After the feature enabled on your smartphone, you will a new three-tab layout on WhatsApp, one each for Calls, Chats and Contacts.
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