Jio new monsoon Rs.501 phone exchange hungama is about to start from 20th July 2018.
Customers with any old feature phone brought after 1 Jan 2015 can exchange it for Rs.501 for a brand new Jiophone.

Following conditions would be checked by handset vendor before giving out exchange or one can say below only phones with below conditions met are eligible for exchange:

1. All working mobile phone which are sold from 1st jan 2015 afterwards are eligible for exchange.
2. 2G,3G,4G Non VoLTE device will be accepted for exchange.
3. Jio Phone, any CDMA or Operator locked device will not be accepted.
4. Apart from battery and charger, no other accessories are required for exchange.

Don’t accept the following cases:
1. LCD Damage
2. Spot on screen
3. Broken case/back cover
4. Burnt or adjusted by tapes
5. Swallow battery
6. Broken, burnt and damaged chargers.

That means locked, cdma, damaged, broken screen not working phones won’t be exchanged.
Also if I am reading it correctly only phones models still selling after 1st jan 2015 would be eligible.
I hope they don’t ask for invoice taking it as phone sold after 1st jan 2015.
Let see how this offer unfolds for everyone.