Battlegrounds Mobile India recently received update 1.7 that brought League of Legends Mirror Island. However, many players reported that they were not able to claim the Mirror World lobby theme. Krafton has released a hotfix that lets users claim the lobby theme, provided they have the updated app.
BGMI 1.7 update hotfix: Krafton via its BGMI blog post announced that players will be able to claim the Mirror World Lobby theme from November 23 till December 22.