Krafton has confirmed that this will be the last month that PUBG: Mobile players will be able to transfer their old game data to Battlegrounds Mobile India. After this, those players will lose all of their previous purchases and achievements to BGMI. As such, any player who has not linked the accounts yet should do so as soon as possible.
PUBG: Mobile to Battlegrounds Mobile India data transfer – Final date
Krafton notes that data transfer between PUBG: Mobile and Battlegrounds Mobile India will no longer be available after December 31, 2021, 23:59:59 (UTC). This is roughly January 1, 2022, 5:30am IST.
It should be noted that data transfer can only happen if PUBG: Mobile players linked their accounts with Twitter. Those who use guest accounts are out of luck as this means their progress from the previous game will be lost forever and they will have to start all over again.