Optional annual return filing allows small taxpayers to opt for past-year compliance; returns not filed are deemed filed if overdue. Eligible registered persons with aggregate turnover not exceeding the specified threshold who had not furnished the annual return under section 44(1) read with rule 80(1) before the due date are permitted to follow a special procedure to optionally furnish the annual return for the identified financial years; returns not furnished before the due date shall be deemed to have been furnished on the due date, and the notification is effective retrospectively from the stated effective date.