Deadline: The deadline for filing your tax return for the income received in August 2021 (FY 2021-22) was July 31, 2022 (or December 31, 2022, for a belated return). It is no longer possible to file a standard return for that year.
Tax Obligations: Royalty income is fully taxable in India. You should keep records of any foreign taxes withheld to potentially claim credit, though you should consult a Chartered Accountant (CA) to assess if there are any outstanding compliance requirements or penalties applicable to your specific situation given the current date.