Special procedure for composition taxpayers requires quarterly CMP-08 statements and annual GSTR-4 return to validate tax compliance. Registered persons paying tax under the composition scheme or availing the departmental notification must furnish a quarterly statement in FORM GST CMP-08 detailing self-assessed tax payments by the 18th day of the month following each quarter, and must furnish an annual return in FORM GSTR-4 for each financial year on or before the 30th day of April following the end of that financial year; submission of these forms for the relevant period is deemed compliance with the statutory return obligations.