Yes , Its true you can enjoy WhatsApp free for ever and anywhere. Currently whatsapp do not charges anything from Indian Users. However it charges from users residing in European Countries.
As you know that whatsapp charges Rs.50 as annual subscription soon after completion of your first year usage. To enjoy it completely free your mobile must support dual sim feature. Now what next ???…What to do ???
Step 1: Inside whatsapp Goto settings ->Account->Change Number as in figure
Simply put your existing whatsapp mobile number in the old one and 2nd mobile number in the new number textbox. Dont worry you will loose nothing, neither group nor your friends list. You will get new expiry date of your subscription. Your older account would be deactivated.
Now you will have new expiry date. Next , again goto change number and put the old number as your new number , new one as the old number. Doing this ,will not change your fresh expiry date. Applying this trick again when you are about to reach your expiry date , practically you will never reach on expiry and continue enjoying free subscription