1. ROOTed device
2. Any Root File Explorer or SharedPreferences Editor
This trick was working only till version 2.17.81.. So, it will no longer work on newer versions. (All you can do now is switch to older versions to get rid of the feature)
It seems WhatsApp used this to enable the feature to all updated devices (of specific groups) at once when needed, instead of just immediately enabling the feature when it's implemented in the app.
Since it has seemed to them the feature is stable, the condition checking for status_mode was removed, and status feature has been made permanent.
0. Force Stop WhatsApp before proceeding.
1. a. For Root Explorers, open the file '/data/data/com.whatsapp/shared_prefs/com.whatsapp_preferences.xml'
b. For SharedPreference Editors, select 'WhatsApp' and then select 'com.whatsapp_preferences'.
2. Find the key name: 'status_mode' and edit its value from '1' and make it as '0'.
<int name="status_mode" value="1"/>
<int name="status_mode" value="0"/>